答案：(1) When it comes to trouble, Mary really knows how to solve it. (2) When it comes to learning, most people hold that reading is a critical way of one’s growth. (3) They got an idea, but when it came to sticking with it and really working at it, they fell silent. (4)WhenitcomestosoftdrinksCoca-ColaisthebiggestsellingbrandnameinBritain. (5)Mostofusknowweshouldcutdownonfat.Butknowingsuchthingsisn'tmuchhelpwhenitcomestoshoppingandeating. (6) No matter where I go (=Wherever I go) , I will be thinking of you. (7) No matter how hard you try(=However hard you try), you will never be successful. (8) No matter whether it is light or dark at that hour, we’ve decided to leave at 5 in the morning. (9) The manager decided to give the job to whoever he believed had a strong sense of responsibility. (注：此句中，whoever引导宾语从句，做介词to的宾语，不能用no matter who 替换，另外he believed是插入语) (10) In fact, whoever works hard can be whatever they want to be, whether it is a singer, a CEO, or a teacher. (注：whoever works hard为主语从句，做整个句子的主语，所以whoever不能替换成no matter who；whatever they want to be是表语从句；因此whatever也不能替换成no matter what.)
