Thirty years ago this month，China's leaders launched an economic revolution.___________the door to free market reforms and foreign trade．
| A．to open | B．opened | C．opening | D．having opened |
The school requested that all the students ____ school uniform on weekdays in school.
| A．wear | B．wore |
| C．wears | D．have worn |
Bats are surprisingly long-lived creatures, some _____ a life span of around 20 years.
| A．having | B．had | C．have | D．to have |
I often think of those occasions ______ we had a happy time together.
| A．which | B．when |
| C．on which | D．Both B and C |
Every day _____a proverb aloud several times until you have it memorized.
| A．read | B．reading | C．to read | D．reads |
In April, thousands of holidaymakers remained ______ abroad due to the volcanic ash cloud.
| A．sticking | B．stuck |
| C．to be stuck | D．to have stuck |