具有解热镇痛及抗生素作用的药物“芬必得”主要成分的结构简式如下,它属于①芳香族化合物;②脂肪族化合物;③有机羧酸;④有机高分子;⑤芳香烃
The CDs are on sale! Buy one and you get ______ completely free.
Progress______ so far very good and we are sure that the work will be finished on time.
Charles was alone at home, with_______ looking after him.
It is often ______ that human beings are naturally equipped to speak.
I’m sure that your letter will get______ attention. They know you’re waiting for the reply.