while 后面必须借动词的ing形式吗?
She listened to her favourite rock music while singing along with the words.
She was putting on her jeans while asking me to hand her the sweater.
He banged on the door while opeaning it.
In the bathroom she put on some makeup while loojing in the mirror.
The school master looked angrily at the naughty student while talking with his parents
看了很多例句都是这样,为什么必须加V-ing?而when后面为什么可以加动词原形呢》
when 后面加非延续性动词，为什么就是正常的过去时？
while 后面加延续性动词为什么就是ing形式？