The children，__________ had played the whole day long, were worn out.
| A．all of what | B．all of which |
| C．all of them | D．all of whom |
--Mary, have you got my email? I sent you a birthday card yesterday.
---Oh, really! I haven't ＿＿＿my mailbox yet.
| A．seen | B．checked | C．received | D．answered |
I haven't settled the problem of I'll go back home during the coming May Day.
A which B. what C. whether D. where
---Don't be so naughty! Be your ________.
---Got it.
| A．manners | B．age | C．behavior | D．politeness |
--Excuse me, sir. Would you do me a favour?
---Of course. What is it?
---I ________ if you could tell me how to fill out this form.
| A．had wondered | B．was wondering | C．would wonder | D．did wonder |
The factory was built in a secret place, around ________ high mountains.
| A．which was | B．it was | C．which were | D．them were |