依次填入下面一段文字横线处的语句，衔接最恰当的一组是（ ） 古人不仅把天鹅说成神奇的歌手，他们还认为， ， 。据他们说，天鹅发出这样柔和、动人的声调，是在它将要断气的时候， 。 ， 。①对生命作一个哀痛而深情的告别②用和谐的声音作为它最后叹息的前奏③低沉地、悲伤地构成自己的丧歌④在临终时有所感触的生物中，只有天鹅会在弥留时歌唱⑤这种声调，如怨如诉

__________ the students who have taken part in the sports game is unknown.

When did he meet his wife for the first time？—It was _________ he came back from Africa that year _________ he met his wife.

He’s never stolen anything before，______ he—______ ．It’s his third time to be taken to the policestation．

Mr Cooper wanted to buy the house and he told me that ______ the house cost, it would be ______ it.