26．______ some teenagers don’t realize is _______ difficult life can be after they get addicted to drugs．
| A．What, how | B．That, how | C．What, what a | D．That, what |
Today some people call Amsterdam the “City of Bicycles”____ the convenience for bicycles there.
| A．while | B．before | C．because | D．because of |
Not long after his return, a local war ____ near his town.
| A．broke in | B．broken into | C．broke out | D．broke down |
Later, these rocks proved that ___ in the distant past the Antarctic was covered by plants.
| A．at one time | B．at a time | C．at times | D．at the same time |
The prisoners then wrote the stories in a book called “The Description of the World”, ____ became one of the best-selling books in Europe.
| A．it | B．which | C．that | D．where |
Could you help me to find out the reason ____ the brake doesn’t work?
| A．when | B．how | C．why | D．in which |