1.less 2.called 3.gravity three fourths 4.be able to 表示有做什么的能力,而can是可以做什么,could是过去式或委婉语气 5.have trouble in doing sth. 6.D 7.B 8.make sb do sth. 9.mark 10.集体名词,没复数
1 less 2 called 3 G-force; three quarters 4 can 强调能力;could表示请求;be able to表示主观能力 5 have trouble in doing sth 6 D.more;any other 7 B.making 8 make sb do; make是使役动词,不定式省to 9 先分子再分母,分母要用序数词,大于一用复数 10 有复数 humans