Unlike the fossil fuels of today, biofuels are renewable sources, which mean that they will not ____ easily.
| A．come out | B．break out | C．turn out | D．run out |
It was in the remote mountain areas I spent the gap year I learned how to work with a group of strangers and how to look after myself.
| A．where; that | B．when; that | C．where; when | D．that; where |
--- What are you busy with?
---The exhibition ____ in the city next week．
| A．held | B．will be held | C．to be held | D．being held |
---Jack can't concentrate on his study recently．
--- Yes, that might ____ why he did so badly in the last test．
| A．answer for | B．apply for | C．call for | D．account for |
I can hardly remember any occasions ____ I get caught in a traffic jam in our town．
| A．which | B．that | C．where | D．when |
Holiday shopping ___be a tiring experience．There are so many places to visit and choices to make．
| A．can | B．may | C．shall | D．will |