问题
选择题
Is oxygen the only gas ________ helps fire burn?
A.that
B./
C.what
D.it
答案
答案:A
考查定语从句。Gas为先行词,在定从________ helps fire burn中作主语,且that作主语时不可省略。所以选A。
Is oxygen the only gas ________ helps fire burn?
A.that
B./
C.what
D.it
答案:A
考查定语从句。Gas为先行词,在定从________ helps fire burn中作主语,且that作主语时不可省略。所以选A。