赞同曾老师的解答。

If he can't chop vegetables with one hand he simply uses his feet.

If you open it, you will find a smaller doll inside. (讲述的一种套娃玩偶)

这二句都属于0条件句。所谓0条件句指的是从句表示的为事实，主句表示从句动作发生后的结果。从句和主句所表示的时间都是现在。典型的谓语形式为从句和主句都用一般现在时态。但0条件句的谓语形式也有变体，主句也可以用will do的形式，此时will并非表示将来时间，而是表示习惯意义（这个习惯现在依然存在）。因此，第一句simply uses可改为will simply use, 第二句will find也可改为find。

关于0条件句的定义和可能的谓语动词形式，可参读《维基百科》有关内容：https://en.wikipedia.org/wiki/English_conditional_sentences#Inversion_in_condition_clauses

Zero conditional[edit]

"Zero conditional" refers to conditional sentences that express a factual implication, rather than describing a hypothetical situation or potential future circumstance (see Types of conditional sentence). The term is used particularly when both clauses are in the present tense; however such sentences can be formulated with a variety of tenses/moods, as appropriate to the situation:

• • If you don't eat for a long time, you become hungry.

  • If the alarm goes off, there's a fire somewhere in the building.

  • If you are going to sit an exam tomorrow, go to bed early tonight!

  • If aspirins will cure it, I'll take a couple tonight.

  • If you make a mistake, someone lets you know.

The first of these sentences is a basic zero conditional with both clauses in the present tense. The fourth is an example of the use of will in a condition clause^[1] (for more such cases, see below). The use of verb tenses, moods and aspects in the parts of such sentences follows general principles, as described in Uses of English verb forms.

Occasionally, mainly in a formal and somewhat archaic style, a subjunctive is used in the condition clause (as in "If the prisoner be held for more than five days, ...). For more details see English subjunctive. (See also § Inversion in condition clauses below.)

Use of will and would in condition clauses[edit]

As noted above regarding the first conditional, will (or shall) is not normally used to mark future time reference in a condition clause; instead an ordinary present tense is used:

• • If she wins (not: will win) tomorrow, I'll eat my hat.

However, there are certain situations where will can appear in a condition clause. One type of situation is referred to above under zero conditional, where will expresses futurity, but the sentence as a whole expresses factual implication rather than a potential future circumstance: "If aspirins will cure it, I'll take a couple tonight" (the taking is not a consequence of the curing, but a consequence of the expectation that they will cure).

More commonly, will appears in condition clauses where it has a modal meaning, rather than marking the future. (See uses of will.) Relevant meanings include willingness, persistence, or strong disapproval ^[1][3][4]

• • If you will excuse me, I think I will slip into something more comfortable. (willingness)

  • If you will keep all the windows shut, of course you'll get headaches. (persistence)

  • A: The zookeeper was really annoyed with me.

  • B: Well, if you will throw stones at the animals, it's not surprising! (strong disapproval)

In the second and third sentences will is stressed, and cannot be contracted to "'ll."