题干
Over 20 countries joined to search _________ Flight MH370 in the southern Indian Ocean.
A：of
B：for
C：in
D：from
答案(点此获取答案解析）
B
Over 20 countries joined to search _________ Flight MH370 in the southern Indian Ocean.
A：of
B：for
C：in
D：from
所警示的是