Hello, teachers!
Would you please tell me which is natural in the place of B?

A: This dress doesn't fit me. It's somewhat loose. Do you carry another size?
B: [________]
1. Yes, try this on.
2. Yes, try on this.

A: I will wake up Tom. You wake up Jane.
B: [________]
1. No. I will wake up him! You cover her!
2. No. I will wake him up! You cover her!

Thank you very much.
Pronouns (e.g., personal 'him', etc.) are not compatible in that environment. Allow me to explain using an alternative example:

A. Hang the phone up.
B. Hang it up.

In A. and B. the (pro)noun sits next to the verb. That is, it is in close proximity to the head of the phrase it's housed within:

A. [ [hang] [the phone] [up] ]
B. [ [hang] [it] [up] ]

Now, ungrammatically sets in when the pronoun, not the noun, is moved away from its head:

C. Hang up the phone.
D. *Hang up it.

Certain types of phrasal verbs require a nominal object that's semantically independent (i.e., a noun). Pronouns won't work in that environment because they are semantically dependent on an antecedent, which is why D. above and 1. below sound odd to us.

1. *No. I will wake up him!

'him' is not specific enough, semantically. The reason certain phrasal verbs require a noun has more to do with the semantic make-up of those verbs than it has to do with the structural make up of the grammar (i.e., syntax).

Now, if the pronoun is a demonstrative e.g. 'this' as show below, it sounds perfectly fine:

1. Yes, try this on.
2. Yes, try on this.

The difference between demonstrative pronouns and personal pronouns (the non-possessive sort, of course) is the former also function as adjectives, which makes it possible for us to pick up the nominal, or specified meaning from the context.

A: This dress doesn't fit me.
1: Yes, try this (dress) on.
2: Yes, try on this (dress).

A: No one's on his phone.
1: Hang his Emotion: phone up.
2: Hang up his Emotion: phone.

A: Whose father should we wake up?
1: Wake his (father) up.
2: Wake up his (father).

I hope that eased some for your pain.
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Thank you, Casi!

Your answer is great help to me!

Enjoy the snow flurries on a not-working day!
Thanks again for your kind work on a not-working day.
You're welcome, Jandi.

By the way, try, non-work day. "not" modifies verbs, and "non" modifies nominals. In that context, 'working' functions as participial adjective, a nominal, so it should be "non-working", but since 'working' modifies "day", and days don't actually do labour, use a simple noun, "work", as an adjective: "a non-work day"

All the best, and thank you for your kind words. SMILE
Thanks again for your correction!

Have a nice non-work day! SMILE
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Have a nice day off, too. SMILE