Question

选择 Tom said sorry to kate because he took her umbralla _________

1.Tom said sorry to kate because he took her umbralla _________
A.by accident B.for accident C.by mistake D.for mistake

2.Wow!How beauiful the dresses are!I can not decide__________
A.what to buy B.what to choose C.which to buy D.to buy which
带原因

Answer 1

1. C  by mistake 表示不小心犯的错误，本句为他不小心错拿了她的雨伞

2. C  根据前句感叹句可知，有多种漂亮的裙子可选，故我不知道该选哪一件，用which. 用what的情况举例如下：I am in the supermarket but i don't know what to buy. 仔细体会

Answer 2

1 C
by mistake 固定词组“ 错误地；由于差错"

2 C which one to buy
不定式与疑问词连用“ 我不能决定买哪一件”