为什么只能用lenrn about animal 不能用learn from animal意思上可以啊

为什么只能用lenrn about animal 不能用learn from animal意思上可以啊 为什么European前面只能用a而不是an? 为什么只能用whether he's going to stay at home____two days.为什么不能用about只能用for?如题 为什么只能用 quite 来形容 an exciting place,而不用very He talked about the teachers and schools ________ he had visited.A.that B .which为什么只能用that . he is the person about whom they are talking.这里关系代词是不是只能用whom 为什么呀 I’m looking for some information about famous people ______ I need to make a poster.为什么只能用which 不能用who What are you looking for?I’m looking for the CD about EXO ___ I bought yesterday.为什么只能用that不能用which to my great joy ,i passed the exam and got an a in it.为什么只能用joy而不能用enjoyment father went to his doctor for __ about his heart trouble.A.an advise B.advise C.the advise为什么不用c？不可数名词不能用the吗？ later 和after 的区别为什么有的地方只能用later不能用after呢?e.g.：I flet thirthy again an hour later (right)I flet thirthy again after an hour (wrong)为什么? 电磁炉为什么只能用铁制锅?不能用铝的、什么的? ,为什么灯泡不能用I2R判断功率?只能用U2/? 祈使句只能用and不能用then吗?为什么? 为什么不能用recieve respect,只能用earn/get respect 为什么酒精灯只能用火柴去点? NO为什么只能用排水法收集?