Combination of 2 relative clauses

Robby zhu posted:

Are both grammatical？

Yes, Robby zhu, both sentences are grammatical.

Robby zhu posted:

Someone says there is a difference in meaning: the first implies you recommend more than one, whereas the second means you recommend only one. Is that true?

Yes, it is true. In the first sentence, "who should be sent to work there" restrictively postmodifies "a man whom you recommend." Therefore, that sentence is saying that, of the men whom you recommend, it is the one who should be sent to work there that the speaker does not quite trust. There is more than one man whom the speaker recommends, but only one of the men whom the speaker recommends should be sent to work there, and it is that man whom the speaker doesn't quite trust.

In the second sentence, both relative clauses are still restrictive, but they separately modify the singular noun. Therefore, only one man is being referred to, namely, the man who is identified by the two properties specified by the two coordinated restrictive relative clauses, "whom you recommend" and "who should be sent to work there." In other words, there is a man of whom it is true that the speaker recommends him and he should be sent to work there, and that is the man whom the speaker does not quite trust.

Thanks for your confirmation, David.

Two further questions

1. In the first sentence, does the meaning remain the same if I drop "who",

- I don't quite trust the man whom you recommend __ should be sent to work there.

2. If I make a little change, 

- I don't quite trust the man whom ____(be) recommended who should be sent to work there.

Should I use the singular or plural form of "be" ?

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Robby zhu posted:

Two further questions

1. In the first sentence, does the meaning remain the same as if I drop "who",

- I don't quite trust the man whom you recommend __ should be sent to work there.

No, the meaning does not remain the same at all. With that change, the sentence has one relative clause, not two, and "whom" goes from being correct to being incorrect.

Can you see a difference between recommending someone who should be sent to work there and recommending that someone should be sent to work there?

Robby zhu posted:

2. If I make a little change, 

- I don't quite trust the man whom ____(be) recommended who should be sent to work there.

Should I use the singular or plural form of "be" ?

If you want to passivize, you will have to change "whom" to "who" and then use the singular ("is"): I don't quite trust the man who is recommended who should be sent to work there. If you were actually trying to say something, we could talk about stylistic niceties. I'm assuming this is just a grammar exercise.