Into the dark apartment ___ ,who was quite surprised when everyone shouted “Happy Birthday”.
| A．did David walk | B．David walked |
| C．David did walk | D．walked David |
Nowadays, most people，in order to keep fit，prefer walking to driving ____necessary.
| A．if | B．unless | C．in case | D．as if |
The expo will be held in Shanghai, _____a lot of advanced technology will be shown for the first time.
| A．where | B．which | C．when | D．from which |
We ____ last night, but we went to the concert instead.
| A．must have studied | B．might study | C．should have studied | D．would study |
_____with this challenge, he should meet it without any hesitation.
| A．Facing | B．Having faced | C．Being faced | D．Faced |
Only when we are abroad ____feel how important English is.
| A．we will | B．do we | C．will we | D．are we |