Part V Complete the sentences
61 . We learn how _______ ( 如何使用这种机器 )
62 . Mr Smith is very busy, so you’d better ______ ( 预约 ) before you go to see him .
63 . Eating too much is ________ (对你的健康有害)
64 . You must _________( 戒烟 ).
65 . Don‘’t forget_________ ( 寄信 ).