这句话是否有错误:For example,it's easy for a child to wake up and kn

这句话是否有错误:For example,it's easy for a child to wake up and know where they are.
For example,it's easy for a child to wake up and know where they are.a child 与they are是否不太一致?要么把a child 改成children,要么把they are改成he/she is?这是初中英语Go for it八下Unit 1 P.8 的一句原话