the girl on the bus began to sing a pop song.The girl on the bus began to sing a pop song and soon all the others_________.A.joined B.joined in C.attended D.took part inA 为什么不行 省略(her)

the girl on the bus began to sing a pop song.The girl on the bus began to sing a pop song and soon all the others_________.A.joined B.joined in C.attended D.took part inA 为什么不行 省略(her)
the girl on the bus began to sing a pop song
.The girl on the bus began to sing a pop song and soon all the others_________.
A.joined B.joined in C.attended D.took part in
A 为什么不行 省略(her)

the girl on the bus began to sing a pop song.The girl on the bus began to sing a pop song and soon all the others_________.A.joined B.joined in C.attended D.took part inA 为什么不行 省略(her)
join做及物动词时：
1.连结;使结合[(+to/together/up)]
He joined the two pieces of wood together with glue.
他用胶水将这两块木料粘在一起.
2.与...会合;与...交接
This path joins the highway up ahead.
这条路在前面与公路相接.
3.和...一起做同样的事;和...作伴[(+in/for)]
Will you join us for dinner?
你和我们一起吃晚饭好吗?
4.参加;作...的成员
I'll persuade him to join our club.
我将劝他加入我们的俱乐部.
5.邻接
The two houses join each other.
这两栋房子相互毗连.
6.回到(岗位等)
After a few days on shore the sailor joined his ship.
在岸上待了几天后,水手回到了他的船上.
join做不及物动词时：
1.会合;相遇
Where do the two rivers join?
这两条河在什么地方会合?
2.参加;同...一起[(+in)]
He never joined in the usual sports of the boys.
他从不参加孩子们的一般体育活动.
3.邻接
The two estates join at the foot of the hill.
这两处房地产在山脚下相毗连.
简单来说,就是join是及物动词,直接加宾语,宾语是组织等,join in中join是不及物动词,等于take part in 后面加一个活动等

A表示加入一个团队，而the girl 只是个体

join后直接加宾语的情况通常是----宾语是army(军队),party(党派)....这些特定词汇
join in加宾语，宾语通常为一些活动
希望对你有帮助！