______ environmental damage is done，it takes many years for the ecosystem to recover．
| A．Even if | B．If only |
| C．As if | D．Once |
—I really can’t thank you enough, sir.
— __________.
| A．That’s the most I could do |
| B．I’m glad to have been of help |
| C．No problem |
| D．With pleasure |
Jenny is quite good at taking notes. She can _______ almost every word her teachers say in class.
| A．set about | B．set aside |
| C．set down | D．set out |
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 |
--So you gave Lucy your iPad?
--_______ I just lent it to her.
| A．That's OK | B．Not exactly |
| C．It doesn't matter | D．No problem |
The companies are working together to create they hope will be the best means of transport in the 21st century.
| A．which | B．that | C．what | D．who |