1. word
ground: reason, because
ground作为理由理解的时候通常为复数
valid/ethical ground
ground of/on
there is no ground for…… 不必……
on the fround of/that 以……为理由，因为……的理由，以……为根据
a ground for 一个……的理由
2. translation
因为英语不够好，他拒绝了邀请。
He refuses the invatation on the ground of his poor English.
3. usage
我经常以自己没有时间为理由不去做一些很重要的事情
On the ground of lack of time, I used to delay to do something which really significant.
