On Christmas Eve, we put up some balloons to _______ the festival atmosphere.
| A．make for | B．add to |
| C．add up | D．join in |
All ________is needed for life on board the submarine comes from the ocean.
| A．/ | B．what | C．that | D．which |
Your pen________smoothly. Where did you buy it?
| A．writes | B．is written | C．wrote | D．was written |
All of people in the world should enjoy equal treatment, ________race, religion or sex.
| A．instead of | B．because of | C．regardless of | D．as a result of |
We forbid _____ in the reading room. That is, you are forbidden _____ in the reading room.
| A．to smoke; to smoke | B．to smoke; from smoking |
| C．smoking; smoking | D．smoking; to smoke |
The flu is believed________by virus that likes to reproduce in the cells inside the human nose and throat.
| A．causing | B．being caused | C．to be caused | D．to have caused |