—Shall we go out for a walk?
—I'm afraid not．We can't go out ___ our work is being done．
| A．before | B．until | C．as | D．after |
John is very lazy. He falls ______ behind among the students.
| A．very | B．still | C．more | D．far |
The government must be very _____ about setting policies and make no decision until they are quite sure it is the right one.
| A．particular | B．concerned | C．cautious | D．certain |
I don’t understand how he can say that everything is fine _____ it’s so obvious that it’s not.
| A．unless | B． in case | C．so that | D．when |
Please remember to _____ a stamp _____ your envelope before you post it to your friend.
| A．attach; to | B．fasten; to | C．tie; to | D．stick; by |
--- Have you heard that Mo Yan was awarded the Nobel Prize in Literature last year?
--- _____. He has made a positive contribution to that field.
| A．Congratulations | B．You must be joking |
| C．He deserves it | D．By no means |