In the west, people make _______ a rule to send Christmas present to their relatives and friends.
| A．this |
| B．that |
| C．it |
| D．the following |
The cost of sales makes up a large part of the prices that _____.
| A．are paid for all products |
| B．all products are paid |
| C．for which all products are paid |
| D．for all products paid |
The captain stood by the window, _____ he could see the top of the tower.
| A．where | B．from which |
| C．from where | D．which |
That was the only gate _____ we could rush out and save those _____ were in great danger.
| A．that; which | B．which; who |
| C．through which; who | D．at which; who |
All of the flowers now raised here have developed from those _____ in the forest.
| A．once they grew | B．they grew once |
| C．that once grew | D．once grew |
On the table she found a piece of paper _________some puzzling secret codes.
| A．which was written | B．that was written |
| C．on which were written | D．on that were written |