1】He has to get off the bicycle and push it up on the hill.
有几点很重要：句中没有明确是过去发生的事情时,应用一般现在时have to,由于he 他是第三人称作主语,所以have 改成has;另外同句中第二次提到自行车只要用it替代就行了
2】These gloves will protect your hand from frostbite.
protect from保护……免于……
3】I found it difficult to keep up with the latest fashion in clothes.
我想这道题暗考一个考点:I found difficult to do sth.
我发现做某事时困难的
4】people usually judge the others by their appearance.
这句话还有其他说法,不过这样说最符合题目要求
5】He seems as if he didn't sleep all night.