A DC servo-motor is a type of ( ) applied to automatic control systems A: actuator B: amplifying element C: correcting element D: measuring element

下列哪项是移除属性值（  ）。 A: getAttribute() B: removeAttribute() C: hasAttribute() D: appendChild()

‎下列哪项是移除属性值（ ）。‏ A: getAttribute() B: removeAttribute() C: hasAttribute() D: appendChild()

If A is a matrix, the function max(A(:)) is ( ). A: to return the first element B: to return the maximum element in each row of the matrix C: to return the maximum element in each column of the matrix D: to return the largest element of the entire matrix

CSS中让元素隐藏，但是不清除元素的方法是（ ） A: element { display: none; } B: element { display: block;} C: element { visibility: visible; } D: element { visibility: hidden; }

In a singly linked list which operation depends on the length of the list.( ) A: Interchange the first two elements of the list B: Delete the first element of the list C: Add an element before the first element of the list D: Delete the last element of the list

‏如何创建一个空元素 （ ）。​ A: document.getElementById('alink') B: document.createElement("元素名") C: element.hasAttribute('元素名') D: a.style.opacity = "1"

如何创建一个空元素 （  ）。 A: document.getElementById('alink') B: document.createElement("元素名") C: element.hasAttribute('元素名') D: a.style.opacity = "1"

two-terminal element

The quality element is ______ .