1.答案：It ; was ;that.
解析:此句話包含了強(qiáng)調(diào)句型：it is...that...的用法,強(qiáng)調(diào)的是句中地點(diǎn)狀語in the park.因句子Tom lost his watch in the park.時(shí)態(tài)是一般過去時(shí),所以要用it was...that.
2.答案：The ;reason；why.
解析：此句話運(yùn)用的是固定句型：The reason why（從句）/for (短語）...is /was that .結(jié)合句子中（he was late)及that這些信息點(diǎn),可以判斷所填內(nèi)容應(yīng)該是：The ;reason；why.
3.答案：That was because
解析：He was late that morning.That was because he had missed the first bus.（先說結(jié)果he was late ,再說原因He had missed the first bus,用That was because...)
如果先說原因,后說結(jié)果,這句話可以這樣說：He had missed the first bus.That was why he was late that morning.
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