What+ⅰs+Mary+look+like是病句吗？
What ⅰs Mary look like是病句吗?
是的，look like 是及物动词，疑问句用助动词do，单三时用does，此句将is改为does
It+look+exciting,修改这句话的病句?
it looks exciting.it它，第三人称，谓语动词要用第三人称单数形式
...he is pretty tallwhat is your teacher like?she...
What does he look like?He is all what does she like?She is clever what does your day look like?He is pretty tallWhat is your teacher likes?She is very ...
look+at+the+two+apples+trees+behind+the+house修改病句...
这里的名词apples应该使用单数形式apple，因为这里是用名词apple来修饰名词tree。在大多数情况下，名词作定语时使用单数形式。