题目内容
____________________(不知如何解决) the problem, Jack turned to his teacher for help. (work)
Not knowing how to work out
解析：考查动词ing作状语。
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题目内容
____________________(不知如何解决) the problem, Jack turned to his teacher for help. (work)
Not knowing how to work out
解析：考查动词ing作状语。