1 . He speaks English fluently. He ___________ have learned English before. (根据句意填空)

2 . The letters were also beautifully illustrated — each must have taken its true author, Tolkien, a long time to complete.
译文: 这些信件有美丽的插图, _____________________。

4 . You must have had some moments when you were disappointed. （英译汉）
你________________灰心丧气的时刻。