—Why did Mr. Green take his 7th grade students to the river yesterday afternoon?
—________ the river.
| A．Cleaned up | B．Cleaning up |
| C．To clean up | D．Clean up |
The keeper of the spring cleared away the leaves and branches, and wiped away the silt(淤泥) that would _______ have choked and polluted the fresh flow of water.
| A．thus | B．otherwise | C．therefore | D．later |
Don’t stand by when you come across________ have difficulty in supporting their family because of serious illness.
| A．Who | B．Whoever | C．Whichever | D．Whomever |
Death toll from Typhoon Haiyan in the Philippines _______ 3,637, after the strongest storm this year destroyed the central part of the country on Nov. 8, 2013.
| A．rose to | B．arose from | C．rose from | D．raised to |
To protect the environment, the local government has put up a lot of ______ to warn the citizens not to litter the ground.
| A．sighs | B．sights | C．signals | D．signs |
Corruption is _______ problem in countries across the world, with developing countries often believed to be more serious, although there is no evidence to suggest this is _______case.
| A．a; the | B．the; a | C．不填; the | D．a; a |