23. We went into a hall, on_____walls hung a few pictures of some famous scientists.
| A．its | B．which | C．whose | D．Those |
____puzzled the mother most was____the son would never agree with her.
| A．What;why | B．That;how | C．Which;when | D．What;where |
—____inthisstreet? —IthinkMr.Blackistherichestman.
| A．Whom do you think is the richest man |
| B．Who do you think is the richest man |
| C．Do you think who is the richest man |
| D．Do you think whom is the richest man |
I haven’t found my watch yet;in fact,I’m not sure____I could haved one with it.
| A．where | B．whether | C．what | D．how |
I was advised to arrange for insurance____I needed medical treatment.
| A．nevertheless | B．although | C．in case | D．so that |
They were surprised that a four-year-old boy should work out such a difficult problem
____they themselves couldn’t.
| A．once | B．then | C．while | D．if |