You should have told me so before.
你早该告诉我的。
Honestly, you might have told me!
说实话,你事先应该告诉我呀!
Somebody should have told me.
应该有人告诉我才是。
'You should have told me!' she flared at him.
“你应该告诉我的!”她气冲冲地对他说。
You should have told us. But it's just like you not to share
你应该早告诉我们的。不过你就是这么个人,把事情都藏在心里。