题目

The Belt and Road initiatives China has proposed to ________ the ancient trade routes that span Asia, Africa and Europe have invigorated China's neighborhood diplomacy.A.reveal B.relieve C.revive D.reverse 答案：【答案】C【解析】考查动词词义辨析。句意：中国提出的“一带一路”倡议，旨在复兴跨越亚洲、非洲和欧洲的古老贸易路线，为中国的周边外交注入了活力。A. reveal揭露；B. relieve减轻，缓解；C. revive复兴；D. reverse颠倒，反转。根据后文“the ancient trade routes that span Asia, Africa and Europe”可知中国提出的已知关于x，y的方程组ax+2y=1+a①2x+2(a-1)y=3②分别求出当a为何值时，方程组（1）有唯一一组解；（2）无解；（3）有无穷多组解．