40．Only by changing the way we live_________ (我们才能拯救地球). (save)

39．A tour guide is_________ (不如……报酬高)as a lifeguard. (well, pay)

38．You can improve your writing skills_________ (通过做这些练习). (do)

37．The advantage of reading English poetry in Chinese translation is_________ (你能更好理解它). (understand)

36．While they_________ (穿越太平洋), their boat hit a whale and sank. (cross)

35．He_________ (一定是美国人) with an accent like that. (must)