他们认为一天刷两次牙是一个好习惯.
They think it's a to brush teeth .
青少年应该被允许选择自己的爱好.
should be to choose their own hobbies.
I like a singer .(自己做曲的)(who)
I learn English .(听收音机)(listen)
The shoes ?(一定是她的)(be)
The soccer ball .(是她的)(belong)