However, the fact that the planes are made out of metal will increase their radar return and make it very hard to completely mask them, Hill said.

然而，飞机是由金属制成的事实将会增强它们返回到雷达的信号，以致使飞机很难完全被遮盖，希尔说。

youdao

For this particular layer mask I don't want to create a hard edge so we are going to use the brush tool to manually create our mask.

对于这个层蒙版，我不想有硬边。所以我们选画笔工具手工建立蒙版。

youdao

Multiple instances of a roll over button used as a mask. Nothing hard to do, just thought I would share this with you.

一对按钮滚动的多个实例作为一个面具。这并不困难的事情，只是认为我会与你们分享。

youdao

The actuarial calculus built around that population has become increasingly hard to mask.

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Wearing hard-hat, paper mask, and gloves I walked around Ground Zero with ministry students giving bottles of water, Red Bull, and chewing gum to first-responders working the pile.

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First of all, it can be hard to get it to fit right, and a mask that doesn't fit won't work properly.

CNN: gas mask