圈出正确的词语，补全句子：English is difficult (for/of) me.

It can play ________ me. （   ）

A．on

B．and

C．with

用适当的介词填空。(6分)
（1）We should be good________ animals.
（2）There are all kinds________ flowers on our planet.
（3）Mary's birthday is ________May.
（4）Pandas live  ________   the southwest  ________   China.
（5）Tom often goes to the library  ________   his friends.
（6）African elephants come________Africa.

We like to work _____ groups.  (  )

A．in

B．at

C．on

(    )

A．The cat is in the tree.

B．The cat is behind the tree.