when Mike wsa four, he was able to rides the bike.怎样改错

be able to do sth = can do sth表示能够做某事．后面接动词的原形，所以句子中的rides要改成ride.

When Mike was four, he was able to ride the bike.
was拼错了
be able to do

When Mike was four, he was able to ride the bike.

当迈克四岁时,他就能骑这辆自行车了.

When Mike was four, he was able to ride the bike.
am is和are的过去形式分别为am is改为was ,are改为were
be able to do有能力做某事,这里的do一定要是动词原形,able 就是能够的意思.
整句话的中文解释就是:当迈克四岁的时候,他就能够骑自行车了.

when Mike was four, he has able to rides the bike

be able to
看到这个to了吗？
to的后面动词要用原形哦
怎么用了第三人称单数呢？
另外，首字母没大写，was拼写错误，一般是不会作为要改的错出在题目里的（哈哈，应该是你打错了吧）
如果有两个错误的话，那么the 也不当
因为the表示特指，用the 就表示他会骑某辆特别的车。所以，如果上下文没有提到那辆特别的车，应该用a 比较妥当。
当然，这也算不上是严格的语法错误。不过在上下文都没有提到那辆特别的车的情况下，这个地方还是可以改出来的。

rides----ride
be able to do sth.能够做谋事

When Mike was four, he was able to ride the bike.
be able to do sth

正确的是：
When Mike was four, he was able to ride the bike.