When the old man ______ to walk back to his house, the sun itself behind the
mountain.
| A．started; had already hidden | B．had started ;had already hidden |
| C．had started; was hiding | D．was starting; hid |
I'll try it again．Never in my life _____ such a particular difficulty．
| A．had I met | B．have I met | C．I had met | D．I have met |
You have a big mouth, Tom．You ___ have told everybody the secret．
| A．can'1 | B．mustn't | C．shouldn't | D．mightn't |
My dog made a mess in the living room, ______ really annoyed me．
| A．who | B．when | C．that | D．which |
They made a great effort to prepare the exhibition, ______ to achieve a big success．
| A．hoped | B．hoping | C．to hope | D．hope |
It is still unclear ______ the little boy got the CD player to work．
| A．where | B．what | C．that | D．how |