何为 CVP ， CVP 监测的适应证有哪些？

青少年牙周炎的好发牙位为(　　)。

A．尖牙

B．第二磨牙

C．前磨牙

D．第一磨牙和切牙

E．所有后牙

只有降低抽样误差才能提高试验结果的正确性。试验结果的正确性包括准确性和（）。

We do not know exactly how many whales there are in the sea because we can’t count them. But we believe at the beginning of the eighteenth century there were 105,000 humpback whales and 120,000 right whales. At the beginning of the twentieth century there were 75,000 humpbacks and 80,000 rights.

Since 1900 their numbers have fallen very quickly. Between 1935 and 1950 the number of humpbacks fell from 20,000 to 10,000 and since 1950 the number has fallen to only 6,000. The number of right whales has fallen even faster. In 1935 there were 25,000. The number fell to 6,000 in 1950 and since 1950 the number has fallen to 4,000. Men have always been hunters. Thousands of whales have become victims(牺牲品). It’s time to do something to protect whales.

小题1:Which of the following is true?

A．We know the exact number of whales in the sea.

B．It’s easy for us to count whales in the sea.

C．We find it impossible to count whales in the sea.

D．We don’t want to know how many whales there are in the sea.小题2:The number of right whales has fallen _______.

A．more slowly than that of humpback whales

B．faster than that of humpback whales

C．as slowly as that of humpback whales

D．as fast as that of humpback whales小题3:The passage is mainly about _______.

A．the number of humpback whales

B．the number of right whales

C．hunting whales

D．the necessity of protecting whales

我国高校的教学组织形式包括（）。

A.课堂教学

B.课外活动

C.社团活动

D.社会实践

关于滑动摩擦力的说法，下列正确的是（）

A.滑动摩擦力的方向总是和物体运动的方向相反；

B.只有运动的物体才受到滑动摩擦力

C.滑动摩擦力总是阻碍物体间的相对运动

D.滑动摩擦力总是阻碍物体的运动