自从美国回来，有很多学生找我解答托福上的一些问题，其中有很多同学说记不住单词或者学校给的单词太多，很难记住。我花费了一些时间，总结整理出托福考试最精华的400个单词，分40个类别，先放9类90个单词。
Group 1 food crops
1.abandon
2.adversely
3.aggregate
4.cultivation
5.fertilize
6.intensify
7.irrigation
8.obtain
9.photosynthesis
10.precipitation
Group 2 disaster
1.anticipate
2.catastrophic
3.collide
4.eruption
5.famine
6.flood
7.impact
8.persevere
9.plunge
10.unleash
Group 3 evolution and migration
1.adapt
2.diverse
3.evolve
4.feature
5.generation
6.inherent
7.migration
8.physical
9.process
10survive
Group 4 petroleum alternative
1.constraint
2.contamination
3.deplete
4.dispose of
5.elementally
6.emission
7.extinction
8.reservoir
9.shrink
10.stable
Group 5 time efficiency
1.adjust
2.arbitrary
3.denominator
4.exponentially
5.infinitesimal
6.maximize
7.parallel
8.proportion
9.rate
10.sequence
责任编辑：sealion1986
