_____ her children，she also has to look after her old parents.[ ]

Mum, ______ is my friend Peter.

There is a teacher’s desk _______ the classroom. Mr. Liu is standing _______ it.

Do you plant trees in spring, Mike-Yes. Many trees ______ in our city every year.

he denied having seen my lost MP4, Ibelieve at least from nobody else can I get better source of information.