This is Mr. Green and this is Mr. Brown.（）

This kind of cloth is durable, cheap and （）.

In looking at the class structure of an entire system, we may find that its inheritance (1) is either wide and shallow, narrow and deep, or balanced. Class structures that are wide and shallow usually represent forests of (2) classes that can be mixed and matched. Class structures that are narrow and deep represent trees of classes that are related by a common ancestor. There are advantages and disadvantages to each approach. Forests of classes are more loosely (3) , but they may not exploit all the commonality that exists. Trees of classes exploit this commonality, so that individual classes are smaller than in forests. However, to understand a particular class, it is usually necessary to understand the meaning of all the classes it inherits from or uses. The proper shape of a class structure is highly problem-dependent. We must make similar trade-offs among inheritance, aggregation, and using relation- ships. For example, should the class Car inherit, contain, or use the classes named Engine and Wheel? In this case, we suggest that an (4) relationship is more appropriate than inheritance relationship. Meyer states that between the class A and B," (5) is appropriate if every instance of B may also be viewed as an instance of A. The client relationship is appropriate when every instance of B simply possesses one or more attributes of A". From another perspective, if the behavior. of an object is more than the sum of its individual parts, then creating an aggregation relationship rather than an inheritance relationship between the appropriate classes is probably superior.

The wholesale price of this coat is $20 and the（）price for it is $28.

The difference between a class A and a class B EPIRB is that the class A EPIRB（）.

There ______ a basketball match between Class One and Class Three this afternoon.

Blanc is the tallest boy in his class.→ Blanc is ____ than ____ in his class.

In a certain class there are 18 boys and 12 girls. If the class average score for a history exam is 90 and the boys’ average score is 86, what is the girls’ average score?

One hundred boys went on a school outing. Eighty-one percent of the boys lost a shoe, 82 percent of the boys lost a sock, 77 percent of the boys lost a handkerchief and 68 percent of the boys lost a hat.　　What is the minimum percentage who lost all 4 items?

If your vessel is underway in fog and you hear one prolonged and three short blasts，this is a （）.

“This room is spacious and cosy”的中文译法是“（）”。

In a class of 160 seniors, the ratio of boys to girls is 3 to 5. In the junior class, the ratio of boys to girls is 3 to 2. When the two classes are combined, the ratio of boys to girls is 1 to 1. How many students are in the junior class?