缺小品词to
　　① 不定式充当各种成分，一般都不能缺少 to。如：
　　She went there ∧ (to) see her mother.
　　He asked me not ∧ (to) go there.
　　I have something important ∧ (to) tell you.
　　② make, let, have, see, hear, notice, observe, watch 等动词变成被动语态时，充当主语补足语的不定式前的 to需还原。如：
　　She was made ∧ (to) do heavy work.
　　The blind man was seen ∧ (to) cross the street.

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