Only when he returned from the exchange program ________ how much he enjoyed it.[ ]

What Tom often told me in the past was he didn’t succeed,he would still go on studying hard until he was successful.

The telephone in the office is not available, it _____ somehow this morning. [ ]

Father, you promised!— Well, ________. But it was you who didn’t keep your word first.

下列各句中,没有语病且句意明确的一项是(　　)