“羊群效应”：羊群平时很散乱，但一旦头羊动起来，其他的羊也会不假思索地一哄而上，纷纷效仿，全然不顾前方是什么。“羊群效应”反映的主要是（  ）

为使飞机在开始滑行时就有一定的初速度，航空母舰装有弹射装置，然后在飞机发动机产生动力作用下做匀加速直线运动最后起飞．某型号的飞机经弹射系统作用后，具有144km/h的初速度，但起飞的速度须达到180km/h．该飞机提供的牵引力为1.32×1⁵N，起飞质量为2.7×10⁴kg，若飞机在跑道上匀加速100m．

B)根据句子意思，用括号中所给的单词适当形式填空。
____  ▲  (wolf) belong to the dog family, living and hunting together.
____ With the money donated, we have   ▲ (success) helped many poor young girls return to school.
____ If we always keep our worries to   ▲  (we), things will get even worse.
____ Our head teacher warned us   ▲ (not fly) kites near power lines in spring.
____ Though it seemed   ▲  (hope) to pass the exam, he still kept on trying.
____ A recent scientific report says three   ▲  (eight) of the school students suffer from sub-health(亚健康).