He was chipping away at the stone.
他不停地凿那块石头。
He is chipping away at my reputation.
他在毁损我的名声。
He was chipping away at the rock with a hammer.
他在用铁锤把那块岩石一小块一小块地敲下来。
He kept chipping away at the problem until he had solved it.
他一直在琢磨这一问题，直到把它解决为止。
He had been chipping away at the problem util it was solved completely.
他一直在琢磨这个问题，直到把它完全解决为止。
He had been chipping away at the problem util it was solved completely.
他一直在琢磨这个问题，直到把它完全解决为止。
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