Depending on the state of the program, a mouse down might start drawing a line, or it might select an object.

根据程序的状态，鼠标按下事件，应该开始绘制一条直线，或者选中一个对象。

youdao

They all sat down at once, in a large ring, with the Mouse in the middle.

他们立刻坐下来，围成一个大圈，把老鼠围在中间。

youdao

Select the text you want to format by holding down the left button on your mouse.

按住鼠标左键选取你想要格式化的文本。

《牛津词典》

What else can you detect as a yes or no answer is the mouse down?

当鼠标点下时，除了检查真假还能检测什么？

哈佛公开课 - 计算机科学课程节选

Scientists have created a mouse with Down Syndrome, and claim it has already revealed unknown features of the human version of the disorder.

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The REX is also designed to offer Windows 8 users more routine tasks, such as mouse pointing and scrolling down pages.

WSJ: Computing Looks to the Eyes

Look for the enemies to start up a power blow and block it to get a chance for a nasty retaliatory strike, and charge up your own power attacks by holding down the mouse button.

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