组图是牙龈瘤患者，有关此病的描述不正确的是（）
A.生长较慢
B.肿块较局限
C.可能导致牙松动
D.为恶性病变
E.可破坏牙槽骨壁
参考答案：D
A．在这一时刻之前0.1s内的位移一定是1m
B．从这一时刻起1s内的位移一定是10m
C．从这一时刻起10s内的位移可能是50m
D．如从这一时刻开始匀速直线运动，那么它继续通过1000m位移所需的时间一定是100s
For many years, people（）electric cars. However, making them has been more difficult that predicted.
A.had dreamed of
B.have dreamed of
C.dreamed of
D.dream of
