几道语法题1.I thought the technician was to blame for the blowing of the fuse,but I see now how I was mistaken.2.For him to be re-elected ,what is essential is not that his policy works,but that the public believe that it is.3.If they will not accept a check,we shall have to pay the cash,though it would be much trouble for both sides.以上三题划横线的错误应如何改正下划线被吞掉了，1是how，2是最后面那个is，3是the cash

1. I thought the technician was to blame for the blowing of the fuse, but I see now how MISTAKEN I was.
2. For him to be re-elected ,what is essential is not HOW his policy works, but that the public believe WHAT it is.
3. If they DO not accept a check, we shall have to pay IN cash, though THERE would be much trouble for both sides.

  how  改为  that
  is  改为  does
the cash  改为 cash