reason/ 'riːzn /

1.noun [c] 
(cause) 原因

2.noun [u] 
(rationality) 理性

3.vi.
to reason with sb 与某人理论

4.vt.
推理

the reason for sth
某事的动机
the reason why
…的原因
to have reason to do sth
 [frm] 有理由做某事
by reason of
 [frm] 因为
with good reason
合乎情理
within reason
在合理的范围内