I'm very tired ________walking for two hours.
| A．of |
| B．to |
| C．from |
| D．by |
______ only 20 minutes to go before the train left, I felt uneasy in the taxi to the railway station.
| A．For | B．With | C．As | D．Because |
If you can make what the teachers teach ________, you’ll make rapid progress.
| A．yours | B．yourself | C．you | D．your |
_______ has recently been done to provide more buses for the people, a shortage of public vehicles remains a serious problem.
| A．What | B．Though what | C．In spite of what | D．However what |
When a giraffe has ______ drink, it has to stand with its front legs wide apart in order to reach ______ water easily.
| A．不填；不填 | B．a; the | C．the; 不填 | D．不填；the |
If we ___________some measures, we might have prevented the environmental pollution.
| A．take | B．had taken | C．took | D．have taken |