She rubs her teeth with her finger _______ she wants to brush her teeth. This is done after every meal.
| A．when | B．until | C．since | D．while |
-What will you do then?
- I’m afraid I can do nothing at present.
| A．but wait | B．but to wait |
| C．except wait | D．except to wait |
The classic superheroes like Spiderman or Superman to many decades ago.
| A．was dated | B．dated back |
| C．date back | D．was dating |
Weather experts advise us out if PM2.5 levels are above 500.
| A．not go | B．not going |
| C．don’t go | D．not to go |
Unemployment is rising and prices are increasing; , the economy is in trouble.
| A．in terms of | B．in a nutshell |
| C．as a result of | D．at a time |
Once considered a of western culture, Valentine’s Day is becoming popular in China.
| A．figure | B．record | C．sign | D．symbol |