Friends play an important part in our lives, but we don&39;t know much about how to make friends. As we get to know people, we consider things like age, races, looks and social positions. Thus it is more difficult for people to become friends if there is a big difference in age and background. However, some people don&39;t think these factors are of the most importance.

A lot of houses were seriously damaged in the earthquake, so that thousands of people were left homeless.

The photo reminds me of the happy time I spent in Shanghai.

Directions According to the given information,you are required to write A Letter to a Friend in about 1OO words. The letter is required to be written on the Answer Sheet.

钢筋的力学性能指标包括___________、___________、___________、___________，其中___________和___________是检验钢筋塑性性能的两个指标。

求微分方程dy/dx +y=e-x的通解．