吸风机检修后，试运时间不得少于（）小时，方可投入运行。
A.2
B.4
C.8
D.24
参考答案：C
合并同类项：①15x+4x﹣10x=( )；②﹣p2﹣p2﹣p2( )
根据Jim’s Family Tree，在横线上填入正确的单词。
Jim’s Family Tree
I 71 a friend. 72 name is Jim. There are(有) eight(八个) people(人) in his 73 .
His grandparents have two sons, his father and his 74 . His parents have two 75 and two 76 . 77 78 Jim, Susan, Henry and Jane. So Jim has two 79 and a 80 . Jim loves his family very much. They love him, too. He has a big and good family.
