仅由顺序、选择（分支）和重复（循环）结构构成的程序是（）程序。
参考答案：结构化程序设计
用括号中所给词的适当形式填空。
1. —________ (do) he ________ (have) a baseball?
—No, he ________ (do not).
2. Let ________ (we) play tennis.
3. —Shall we watch TV? —That ________ (sound) boring.
4. Please ________ (join) us soon!
5. We have so many ________ (club).
我国农村唇腭裂发病明显高于城市，其发生率为
A．1.1%
B．2.1%
C．3.1%
D．4.1%
E．5.1%
