英语题25: I like watching my dog _______(play)around.

问题描述:

英语题25: I like watching my dog _______(play)around.
答案给的是play,我想问一下,为什么狗是第三人称单数不用plays而用play?

watch sb do sth:看某人做某事
watch sb doing sth:看某人正在做某事