1、【题目】Insect pests are among the leading causes of crop failure.
选项：
A.expected
B.chief
C.natural
D.least
答案：
B
解析：
暂无解析
1、【题目】Food must be moist in order to have a taste.
选项：
A.appetizing(delicious)
B.nutritious
C.damp
D.chewed
答案：
C
解析：
暂无解析
1、【题目】Blue－greenalgaegrowabundantlyinsaltmarshes.
选项：
A.primarily
B.slowly
C.onplants(cultivate)
D.ingreatnumbers
答案：
解析：
1、【题目】TheNativeAmericaninterpreterSacajaweawasavaluablememberoftheLewisanddarkexpeditionin1805.
选项：
A.veryfriendly
B.veryuseful
C.verythoughtful.
D.verywealthy
答案：
解析：
1、【题目】TheSalkvaccineisamajorfactorinthefighttoeradicatepolio.
选项：
A.completelydestroy
B.carefullydisguise
C.sustain
D.contain
答案：
解析：
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