myul.appendChild(myli1);//若追加的元素myli1已经存在，则把原来位置的myli1元素删掉，在最后追加。相当于把此元素从开始移到最后
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document.createElement("ul");//可以创建一个ul元素,但是不会自动追加到相应的父元素里面
A. 对
B. 错
mathematical analysis
A. symbolized arithmetic
B. interconnection between variables
C. a rectangular array of numeric or algebraic quantities subject to mathematical operations
D. a statement of equality between two equal numbers or number systems
E. the study of variables and their relationships
algebra
A. symbolized arithmetic
B. interconnection between variables
C. a rectangular array of numeric or algebraic quantities subject to mathematical operations
D. a statement of equality between two equal numbers or number systems
E. the study of variables and their relationships
calculus
A. a statement of equality between two equal numbers or number systems
B. the study of variables and their relationships
C. the branch of mathematics concerning points，lines，angles，surfaces and solids
D. mathematical treatment concerned with random events
E. differentiation and integration
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