____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
____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
A
分词作状语，表示动作发生的时间、原因、方式、结果，或表示伴随状况、补充说明;
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