《礼记》中“鹦鹉能言，不离飞鸟，猩猩能言，不离禽兽。今人而无礼，虽能言，不亦禽兽之心乎？”对这句话理解正确的是（    ）

地球上一切陆生生物的“立足点”是（    ）

B

阅读下面的图表，做51～53小题。

Dolphins live in the water, but they’re not fish.

When they swim, they often jump out of the water.

Dolphins are very friendly to people. Would you like

to learn to the talk on Friday? Call Mr. Lu at

010-82214824.

7.3＋2.7=____   0.91－0.9=____   12.7－12.6=____

4.8＋5.6=____   6.8－3.2=____   6.4＋4.2=____