bank soal : gerund

Please see the following sentences. Please mark C if it is CORRECT, and I if it is INCORRECT.

1. Thank you for helping me type this letter. <.....>
2. Mrs. Jean insisted to know the whole problem. <.....>
3. Billy is in charge organizing the meeting. <.....>
4. The rain prevented us from completing the work. <.....>
5. Starting a quarel with his friend, Jodi must stop it now. <.....>

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