终止读秒
参考答案:
台上裁判员在读秒过程中,如果发现运动员出现休克、关节脱臼、骨折等危险状态时,即刻停止读秒,取下运动员的护齿并用手势请医生将运动员送到后场进行急救处理。
A farmer with 1,350 acres of land had planted his fields with corn, sugar cane, and tobacco in the ratio of 5:3:1, respectively, but he wanted to make more money, so he shifted the ratio to 2:4:3, respectively. How many more acres of land were planted with tobacco under the new system ?()
A. 90
B. 150
C. 270
D. 300
E. 450
如图所示生态系统中能量流动图解部分示意图,①②③④⑤⑥⑦各代表一定的能量值,下列各项中不正确的是()
A.次级消费者的粪便中的能量去路包括在④途径中
B.从能量关系看②>③+④
C.一般情况下,②为①的10%~20%
D.生物与生物之间吃与被吃的关系不可逆转,所以能量流动具有单向性