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本题提取字符串“china is a great country.”中的前5个字符生成一个新的字符串，并将剩余字符组成另外一个新的字符串，最后将两个新的字符串连接输出。
public class java1
public static void main(String[] args)
String str="China is a great country.";
headstr=str. substring();
trailstr=str. substring();
System. out. println(headstr+trailstr)

【参考答案】

第A处：String headstr, trailstr
第B处：0,E
第C处：E,str. length()-A

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