问题
选择题
It has come to be realized ______ particular matters in the air expose us to life's real danger. [ ]
A. what
B. which
C. when
D. that
答案
答案:D
It has come to be realized ______ particular matters in the air expose us to life's real danger. [ ]
A. what
B. which
C. when
D. that
答案:D