请根据句意和汉语提示写出下列各句中单词的适当形式。

小题1:I think math is _____________(困难的)，so I dislike it.

小题2: Where is ________(杰克的) radio? It’s on the table in his room.

小题3: Whose ___________(排球) are these? They are hers.

小题4:“Look at your room, Tom! Your books are__________(到处)！”mom says angrily.

小题5: Do you like__________(听) to music?

主要通风机必须安装2套同等能力的主要通风机装置，其中1套作备用，备用通风机必须能在（）min内开动。

A、10

B、15

C、20