题型:判断题 Fully_________in looking after three children athome ,she no longer has time to enjoy the various activities in the club. [ ]A. occupied B. contributed C. hesitated D. devoted 查看答案
题型:判断题 在影片《铁道游击队》中,为了伏击日军火车,侦察员常用耳朵贴着铁轨来提前判断是否来了火车.这是利用声音在铁轨中的传播速度( )声音在空气中的传播速度.A.大于B.小于C.等于D.以上都不对 查看答案