The spelling of the verb is not such an easy topic as it seems at first glance, and many understand this. Vowels and consonants in the root, endings, prefixes - all this requires special attention. Suffixes in the indefinite form of the verb are also far from simple. Conjugation, the type of verb - they are affected by a very, very much. But this can be easily dealt with, if there was a desire. Let us try to understand what the spelling of verb suffixes specifically depends on, and what kind of suffixes they are in general.
Foundation basis
Any lesson of the Russian language “Indefinite form of the verb” would begin with the definition of the corresponding concept. The infinitive (and this is what it is called scientifically) is the initial, zero form given in the dictionaries and not having any morphological features. So, the indefinite form of the verb: time, person, number and mood are absent, but it has a perfect ( answer ) or imperfect ( answer ) form; category of collateral - real ( pronounce ) and passive ( must be pronounced ); recurrence ( turn out ) and irrevocability ( run ). This word form answers the questions what to do? and what to do? And one of its main features are suffixes in the indefinite form of the verb: - t, t, whose -. Some linguists distinguish such suffixes as - sti - and - sti -.
And how to understand that it is an infinitive?
The definition seems to be sorted out. What next? How to determine the indefinite form of a verb? Is it possible to somehow understand that this is precisely the infinitive, and not something else? Easy! We take the verb we need, for example, to read , and look at its morphemic composition (those parts of the word of which it consists). In this case, there is our suffix - t - in addition, we ask a question to the verb: read - what to do? And the second sign is consistent. To be sure, you can try to determine the face, number and time - and this is impossible. But the view ( what to do? - imperfect), recurrence (there is no postfix -sya - the verb is irrevocable) and the voice ( read - I do it myself - real) are found without difficulty.

Another example is the verb blinking . There is no suffix necessary for us, and to an attempt to ask a question he answers what am I doing? - again, not what we need. It is already clear that in this example there is a person (I blink - the first), and the number (the only one), and the time (present), as well as the type (imperfect), and repayment (irrevocable), and pledge (valid). That is, this word form is not an infinitive.
Before determining the indefinite form of a verb, you need to check it for the presence of basic morphological characteristics. If they are not there, it’s fine, we have an infinitive, but if we have a person, a number and a time, then this is just the inflected form of the verb.
An infinitive ending?
Another very difficult issue for many is the spelling of verb endings, depending on the conjugation. The question is not very easy - first determine what conjugation the verb belongs to, and for this you need to put the verb in our indefinite form, see what it ends with, based on this, if possible, determine the conjugation and only then put the ending in personal form of the verb. With the infinitive, everything is much simpler.
Ending verbs in indefinite form is a topic that does not exist. Now many frown frowningly: after all, somehow we define the same conjugation, do we look at the ending for this? No no and one more time no. The vowel before the infinitive suffixes is another suffix, although some linguists define it as an ending. Mandatory to remember: since there are no morphological signs, then the end of verbs in indefinite form cannot be. Infinitives are characterized by the presence of only suffixes.
Suffix, not ending
Let us return to the final, infinitively-determining suffixes. What determines which one to choose for the verb? Of course, for a native speaker of the Russian language this is not a problem at all - we intuitively feel what to use, but for those who study the great and powerful as a foreign one, such a choice can be very difficult.
The suffix - ti - is usually under stress ( nesti, carry ), and it is also found in words derived from these, when a prefix pulling in itself appears on them ( EXTRACT, EXTRACT ) - most often this is the prefix - you -.
- t - in turn, occurs where there is no stress ( SAY, LAUGH ).
The presence of - sti - and - sti - is typical for verbs whose base ends in - e, t - ( UPADU - DEPRESS, PLAY - PLEST ), the second suffix also exists in verbs whose base in personal form ends in - b - ( grab - sorrow ).
Of course, there are a number of cases when suffixes in an indefinite form of a verb do not obey basic rules, for example, curse - curse, grow , but in this situation we can say that these verbs are peculiar exceptions, so that, no matter how sad it is was, you need to remember.
We complicate the task
In general, it is not very correct to consider only standard ones - t, t, t, t, t, t, tt - as suffixes in an indefinite form of a verb, when speaking about the spelling of this part of speech. There are still suffixes - ova, eva - and - willow, eva -, the choice of which is also associated with certain difficulties. They are found in such words as, for example, profess, talk, lay, and so on.
The spelling of the suffixes of the verbs in this case requires the statement of this very verb in the first person singular (this is what corresponds to the pronoun I ). If the necessary form ends in - uyu, uyu - then you should choose the suffixes - ova / eva - ( stalk-stalk, fight-war-fight ), but if I stumble, scream - will go suffixes - willow, evy - ( Bury - dig in, insist-insist ).
Now complicating things a bit more
Continuing the topic of spelling suffixes is another interesting rule. Those verbs that end in stressed - retain the same vowel before the suffix in the infinitive without this ending, which stands before this suffix in the conjugated form of the verb ( Fill-Fill ).
In addition, there are interesting words that do not quite obey the general rule. In the indefinite form of the verb, the compound suffix is written in them - enet -: KNEAD, DOLBE, and so on.
A bit of a nightmare
Another “favorite” topic by almost all schoolchildren is the spelling of the suffix before - ti, ti, ti, sti, sti - on which the choice of conjugation of a verb usually depends. Of course, sometimes it is obvious, but sometimes, in words like gluing , everything is not as simple as we would like.
In this case, you have to go deeper into conjugations. As you know, verbs have the first and second conjugation. Both of them influence the choice of ending in personal verb forms. The problem is that sometimes the ending in a personal form is obvious, but what to write before the infinitive suffix is not always clear. In this case, we take the controversial verb and begin to conjugate it. If the endings in conjugated forms correspond to the endings of the first conjugation ( -th , -eat, -et, -em, -et, -yut / -out ), then suffixes should be written by which the first conjugation is determined - - ,, - -, if the second ( -y, -y, - look, -it, -im, -ite, -yat / -at ), then, respectively, -it. For example, the same glue - glue, glue, glue - thus, since they correspond to the ends of the second conjugation, you need to write the suffix of this very second conjugation - to.
Finish line: soft sign in the infinitive
Now let's move on to the last of the most important aspects regarding the infinitive. Certain difficulties are caused by a soft sign in an indefinite form of the verb - the hero of a huge number of Internet memes in the style of "the pain of any literate person." In general, it is very difficult to say why such a simple topic seems so heavy, but oh well, and we will deal with it.

Whether or not to write a soft sign in the infinitive is very easy to determine. We take the verb, best in the third person singular (this is what corresponds to the pronouns he, she, it ), and ask a question to him. If the question is what does? , then there will be no soft sign either in this form or in the infinitive ( it learns? what does it do? - learn ), if the question is what to do? , then, accordingly, a soft sign will appear in both forms ( he wants to learn - what to do? - learn ). Of course, it all depends on the context. As you can see from the example, the same verb can be written both with a soft sign and without it. Will we try again?
I can not sleep.
They laugh at a serious conversation - it's stupid.
Why don't we take a walk?
He is too lazy to go outside once again.
He refuses, refuses in this situation - the only way out.
Conclusion
The verb is a part of speech that is multifaceted and complicated, working with it includes a huge number of nuances, little things that should always be taken into account. Verb suffixes are definitely one of the most difficult topics in spelling, but still, if you remember the basic rules, everything will become much easier.

Let us repeat again all that was said above. Firstly, infinitives have no endings, this is a suffix, and that's it. Its choice depends on the stress (under stress - ty -, without it - t -) and on the consonant, on which the stem of the verb ends (if on - e, t, b -, then most likely the infinitive will be endowed with suffixes , st -). Further, on the writing of the suffixes - yva / willow - and - ova / eva -. If the verb in the first person singular ends with - uy / yu - then we write - ova / eva - if there is - yva / willow in this form, then we also keep the suffix. The real war unfolded around the definition of a consonant preceding the infinitive suffix. Here we determine the conjugation by conjugating the verb, and already proceeding from it for the first conjugation with the endings - eat, eat, eat, eat, ut / yut - write - yt / yat / yat - if the endings in the personal form of the verb - eat, um , they, at, at / at - - choose between - at / at -. And the last: when the verb answers the question of what to do ?, we write a soft sign in the infinitive, when what does it do to the question ? do without him.