Mr Brown was much disappointed to see the washing machine she had had_______went wrong[ ]

You can hardly imagine the difficulty the womanhad ______ her children

A good story does not necessarily have to have a happy ending，but the reader must not be left ________.

下面词语中加点的字的读音，没有错误的一项是（ ） （ ）

Last week the students did the experiment in order to_______ if iron rusts in dry air．