一般现在时的意义有：
现在的动作和状态
经常性的东西或状态
客观真理，科学事实
不知道
一般现在时的句型结构：
主语+ be + 其他
主语+ V原/V三单+其他
主语+ was/ were +其他
三单主语有哪些？
I
my mother
you
she
he
they
you and I
Tom often does his homework after school.(改为否定句)
Tom often does his homework after school.(改为一般疑问句)
Tom often does his homework after school.(对does his homework 进行提问)