Of all living creatures on earth, insects are the most plentiful. Some 36 are very useful to man, for example, bees, 37 we get honey and wax, and silkworms, which 38 us with silk. Other varieties, 39 , are extremely harmful, and do a great 40 of damage, especially to crops. Locusts （蝗虫） are perhaps the most dangerous of all, 41 they will eat almost any green 42 , and when millions of them 43 on cultivated land（耕地）they soon leave it 44 . In some countries they are the farmer’s 45 enemy. Another nuisance is the common 46 , not only because it 47 us indoors and out - of- doors, but because it spreads diseases.
Scientists have given much time and 48 to the study of insects. It needs the most careful and 49 observation. Thanks 50 their discoveries we now know almost all 51 is to be known about the habits of these hardworking insects, bees and ants, which live in 52 better planned in some ways than our 53 . But the most valuable work has been done in trying to give 54 to men, animals and crops from the 55 which insects cause.
36．A. members B. forms C. qualities D. varieties
37．A. by which B. from which C. of which D. in which
38．A. give B. produce C. offer D. supply
39．A. however B. meanwhile C. therefore D. what's more
40．A. majority B. number C. amount D. quantity
41．A. and B. for C. if D. when
42．A. grass B. field C. fruit D. plant
43．A. settle B. attack C. pass D. cross
44．A. bare B. nothing C. empty D. untouched
45．A. hardest B. greatest C. serious D. wildest
46．A. insect B. creature C. fly D. enemy
47．A. dislikes B. bites C. worries D. hates
48．A. understanding B. ideas C. comprehension D. thought
49．A. serious B. patient C. curious D. long
50．A. for B. of C. to D. with
51．A. that B. which C. there D. what
52．A. societies B. crowds C. teams D. organizations
53．A. world B. nation C. selves D. own
54．A. help B. protection C. living D. defense
55．A. injury B. wound C. sickness D. ruin
