我经常帮妈妈打扫卫生 I often help my mother ____ ____ ____.

我经常帮妈妈打扫卫生 I often help my mother ____ ____ ____.
汤姆正在学用筷子吃饭
Tom is learning to eat ____ ____.
他一到这儿就来看我
He came to see me ___ after he ____.
在北京大学读书是很幸福的
It's ____ ____ ____ in Beijing University.