执行以下程序段后，变量c$的值是 【7】 。
a$="北京"
b$="Shanghai"
c$="Left(a$,2)+String(3,"—")+Right(b$,8)
参考答案：北京——Shanghai
解析： 本题主是考查了Left、String和 Right三个字符串函数。Left(C,N)函数表示从字符串C的左边取出N个字符。Right(C, N)函数表示从字符串C的右边取出N个字符。String(N,C)函数返回N个指定字符构成的字符串。题中Left(a$,2)的值为“北京”， String(3,"—")的值为“———”，Right(b$, 8)的值为"Shanghai"。然后用运算符“+”将三个字符串连接成一个字符串得：北京—— Shanghai。
| 完形填空。 | ||||
| Billy is a boy of fifteen. His parents died three years ago. One day when he was walking in the street, he 1 a wallet. He returned it to the owner, Mr Baker. He gave his 2 to the boy. As the boy had no job, Mr Baker made him work for him in his 3 . Billy worked so hard that Mr and Mrs Baker were 4 with him. Mr Baker loved planting 5 . The week before last, he brought a few trees home, planted them in the 6 himself and watered them every day. Several days 7 , he had to leave for another city. Before he started, he said to Billy,"Take good care of these trees. Some boys near our house always want to steal them.""Don't 8 about them, sir."answered Billy,"I'll try my best to watch them."Six days passed and Mr Baker came back. He asked," 9 anyone ever come to steal the trees?" "No, sir."said Billy. "To stop someone from stealing the trees, I 10 them up six days ago. I have hidden them for almost a week!" | ||||
|