________such heavy pollution already, it may now be too late to clean up the river.
| A．Having suffered |
| B．Suffering |
| C．To suffer |
| D．Suffered |
Rather than boring TV shows, he always prefers original novels
| A．watch; read | B．watching; read | C．watch; to read | D．to watch; reading |
Listen! Do you hear someone for help?
| A．calling | B．call | C．to call | D．called |
--- I was wondering if we could go skiing on the weekend.
--- ______ good.
| A．Sound | B．Sounded | C．Sounding | D．Sounds |
Not until he left his home ______ to know how important the family was for him.
| A．did he begin | B．had he begun | C．he began | D．he had begun |
500 yuan can ______ all my monthly expenses.
| A．cover | B．spend | C．fill | D．offer |