王技师原设计做一个底面周长和高都相等的圆柱形油桶．结果讨论方案时发现这样做太高了，于是将高度降低50厘米，这样不仅美观实用，而且还可以节省314平方分米铁皮．现在这个油桶的容积最大是多少平方分米？
50厘米=5分米．
油桶的底面半径：
314÷5÷3.14÷2=10（分米）；
油桶的高度为：
2×3.14×10-5，
=62.8-5，
=57.5（分米）；
油桶的容积：
3.14×102×57.5，
=3.14×100×57.5，
=18055（平方分米）；
答：现在这个油桶的容积最大是18055立方分米．
| 完形填空。 | |||
| What do you know about the sea? Everybody knows that the sea 1 beautiful when the sun is shining on it. But it becomes very terrible when 2 a strong wind. If you study the map of the world， you will 3 that about two thirds(三分之二)of the world is the sea. Have you ever been to(曾经去过)the sea？The sea is very deep(深的). In some places the sea is 4 deeper. The 5 mountain(大山) in the world is about 9 kilometers high. While(然而) the deepest place of the sea is almost(几乎)11 kilometers deep. The sea 6 very cold. On the top of the sea the water may be 7 . But if you go down , it becomes colder and 8 In most places of the sea, there are lots of fishes. and plants. Some live near the top of the sea. 9 live deep down. You know the sea water is salty. The water of the Dead Sea is very salty. It is so salty 10 fish can't live in it. What a strange sea! | |||
| ( ) 1. A. sees ( ) 2. A. there are ( ) 3. A. learn ( ) 4. A. very ( ) 5. A. high ( ) 6. A. can ( ) 7. A. cold ( ) 8. A. colder ( ) 9. A. Other ( )10. A. after | B. looks B. there has B. know about B. much B. tall B. can is B. warm B. cold B. Others B. that | C. watches C. there is C. look for C. more C. higher C. can be C. colder C. warmer C. The others C. when | D. looks at D. there have D. think of D. most D. highest D. could D. hot D. warm D. The other D. until |