—How often do you eat out?—________, but usually once a week.
| A．Have no idea | B．It depends | C．As usual | D．Generally speaking |
Only when I left for America ____________ how much I missed my parents.
| A．I realized | B．did I realize | C．I had realized | D．had I realized |
Tina apologized ______ her mother _________ breaking her favourite necklace.
| A．for; to | B．to; for | C．at; for | D．to; about |
Making friends is sometimes hard _________ when you don’t know what to say.
| A．specially | B．extremely | C．especially | D．finally |
They did the experiment in the lab _______ was named after Professor White.
| A．where | B．which | C．the one | D．what |
We must do something to ________ the factories sending out poisonous gases so as to keep the city clean and beautiful.
| A．keep | B．protect | C．permit | D．prevent |