the safety of gas, the government has checked the city"s gas supply syste

题型：同步题难度：来源：

       the safety of gas, the government has checked the city"s gas supply system thoroughly.[     ]
A. To ensure
B. Ensuring
C. Having ensured
D. To have ensured

答案

举一反三

Yao Ming is practicing hard in Houston           himself for the coming new NBA season. [     ]
A. improving
B. improved
C. improve
D. to improve

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       more about the university course, call (920)746-3789.   [     ]
A. To find out
B. Finding out
C. Find out
D. Having found out

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There is nothing more I can try       you to stay. So I wish you good luck.[     ]
A. being persuaded
B. persuading
C. to be persuaded
D. to persuade

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—The last one       pays the meal.
—Agreed. [     ]
A. arrived
B. arrives
C. to arrive
D. arriving

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They said goodbye, little knowing that they were never         again.     [     ]
A. met
B. meeting
C. to meet
D. to be met

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