Ellipsis

Hi, Robby zhu,

@Robby zhu posted:

He refused to lend a hand when he should have. I want to know if this sentence can be used as elliptical for "...when he should (lend)"? Because I think the ellipsis would normally be interpreted as referring to a finite verb, in this case, "refuse."

In this case, "should have" is needed because it refers to the past and what is elided is a perfect, not a simple infinitive:

- He refused to lend a hand when he should have lent a hand.

You can use "should" alone to refer to the present or the future, that is, when what follows is a simple infinitive :

A: I don't want to lend him a hand.
B: Well, you should (lend him a hand).

@Gustavo, Contributor posted:

Hi, Robby zhu,

In this case, "should have" is needed because it refers to the past and what is elided is a perfect, not a simple infinitive:

Thanks, Gustavo.

Actually, there was something wrong with the layout, and I accidentally deleted a word , which made you somewhat misunderstand my perplexity. My bad.

But according to your explanation, doubts have been dispelled.

@Robby zhu posted:

He refused to lend a hand when he should have.
[. . .]
Because I think the ellipsis would normally be interpreted as referring to a finite verb, in this case, "refuse."

Hello, Robby zhu—Just to add one small note to Gustavo's answer, with which I fully agree, Verb Phrase Ellipsis very easily and quite commonly takes a nonfinite verb phrase as its antecedent—e.g.:

• He wanted to eat ice cream, but knew he shouldn't [__].

While it is possible to interpret that sentence as meaning "He wanted to eat ice cream, but knew he shouldn't want to eat ice cream," that would not be the natural interpretation in normal contexts, and syntax does not force it at all.

Thanks, David, for endorsing that usage.