某物体作匀变速直线运动,其位移与时间的关系为s =0.5t + t2 (m),则当物体速度为3 m/s时,物体已运动的时间为 A. 1.25s B. 2.5s C. 3s D. 6s 答案:A 解析: 略Having a trip abroad is
certainly good for the old couple, but it remains_____ whether they will enjoy
it.
A. to see
B. to be seen
C. seeing
D. seen