A clean environment can help the city bid for the Olympics, which ________ will promote its economic development．
A．in nature B．in return C．in turn D．in fact
Letterboxes are much more ________ in the UK than in the US, where most people have a mailbox instead．
A．common B．normal C．ordinary D．usual
I’d appreciate _________ if you would like to teach me how to use the computer．
A．that B．it C．this D．you
—What's the name?
— Khulaifi．_______ I spell that for you?
A．Shall B．Would C．Can D．Might
So difficult it to work out the problem that I decided to ask Tom for advice．
A．I did find B．I have found C．did I find D．have I found
The rescue workers were working around the clock, ________ supplies to Yushu Qinghai Province after the earthquake．
A．to send B．sending C．having sent D．to have sent
