5、把当前目录下的file1.txt复制为file2.txt的正确命令是（） A: A.copy fiel1.txt file2.txt B: B.cp file1.txt file2.txt C: C.cat file2.txt file1.txt D: C.cat file1.txt>file2.txt

linux查看文件内容的命令（) A: A.ifconfig B: B.find C: C.cat D: D.which

若Animal是Cat,Dog的父类，则下列选项中，正确的是（） A: Animal animal = new Cat(); B: Animal a = new Cat(); Cat cat = (Cat) a; C: Animal animal = new Dog(); D: Cat cat = (Cat)new Dog();

Under the tree (). A: did a cat lay B: did lay a cat C: a cat lay D: lay a cat

cat testfile的输出与下面哪个命令相同？（） A: cat＞testfile B: cat＜testfile C: cat＞＞testfile D: cat＜＜testfile

若Animal是Cat,Dog的父类，则下列选项中，正确的是（） A: Animal animal = new Cat(); B: Cat cat = (Cat)new Animal(); C: Animal animal = new Dog(); D: Cat cat = (Cat)new Dog();

5 Didn't you see that'blue cat/blue'cat? A: 'blue cat B: blue'cat

l don’t know () now. A: where is my cat B: my cat is where C: where my cat is D: where my cat

2. She lost a ________. A: small white cat B: cat small white C: white small cat

_______ and caught the mouse. A: A. Up the cat jumped B: B. The cat up jumped C: C. Up jumped the cat D: D. Jumped up the cat