Smoking(know)______ to increase a person’s risk of developing lung cancer.is kno

游客2023-09-22  21

问题 Smoking(know)______ to increase a person’s risk of developing lung cancer.

选项

答案 is known

解析 本题考查被动语态的用法。smoking与know之间是被动关系,所以用被动语态is known。
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