单项选择题
Given：
22.StringBuilder sb1 = new StringBuilder（"123"）；
23.String s1 = "123"；
24.// insert code here
25.System.out.println（sb1 + " " + s1）；
Which code fragment， inserted at line 24， outputs "123abc 123abc"？（）
A.sb1.append（"abc"）； s1.append（"abc"）；
B.sb1.append（"abc"）； s1.concat（"abc"）；
C.sb1.concat（"abc"）； s1.append（"abc"）；
D.sb1.concat（"abc"）； s1.concat（"abc"）；
E.sb1.append（"abc"）； s1 = s1.concat（"abc"）；
相关考题
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单项选择题
Given： Which method will complete this class？（）
A.public int compareTo（Object o）{/*more code here*/}
B.public int compareTo（Score other）{/*more code here*/}
C.public int compare（Score s1，Score s2）{/*more code here*/}
D.public int compare（Object o1，Object o2）{/*more code here*/} -
单项选择题
Given： What is the result？（）
A.test end
B.Compilation fails.
C.test runtime end
D.test exception end
E.A Throwable is thrown by main at runtime. -
单项选择题
Given that the current directory is empty， and that the user has read and write permissions， and thefollowing： Which statement is true？（）
A.Compilation fails.
B.The file system has a new empty directory named dir.
C.The file system has a new empty directory named newDir.
D.The file system has a directory named dir， containing a file f1.txt.
E.The file system has a directory named newDir， containing a file f1.txt.
