but I （could） not understand himbut I could not understand him.but I can not understand him.but I don't understand him.有何区别?是否可以互换?整句意思有何不同吗？

But ,I could not find her/him . i could not swim weel but i ___follow himdid do but I （could） not understand himbut I could not understand him.but I can not understand him.but I don't understand him.有何区别?是否可以互换?整句意思有何不同吗？ I searched everywhere but could not find him. but i could not cross the ocean of your I could give up the whole world but I could not live without you There's something I could not taste but I could feel!中文翻译是啥 can not help but后面接什么When I told him the joke. He _____ a.could not help to laughing b.could not help to laughc.could not help but laughing d.could not help but laugh i wish i could,but i can not.i always miss you every! I could not help but laugh.句子中but是什么词性?什么用法? I could not bear I could not catch I did not love you enough,but you could not make good value. I did not love you enough、but you could not make good value . if I could turn back the time,maybe `But not if the.if I could turn back the time,maybe `But not if the. if I could turn back the time,maybe `But not if the.if I could turn back the time,maybe `But not if the. I should have been here ,but i could not find the time.怎么翻译 i should have been there,but i could not catch the bus