The rationale for this rule is that you cannot distinguish an inherited work item from a direct one at first sight.

此规则的基本原理是您不能立刻从直接工作项中区分继承的工作项。

youdao

Motion across the line of sight can be followed by direct observation.

与视线垂直的运动可以通过直接观测得到。

youdao

The biggest drawback to the technology is that it cannot travel through walls, because it requires a direct line of sight between the transmitter and the user's device.

这项技术最大的缺点是不能穿透墙壁，因为它要求发射器和用户设备可以通过直线连接。

youdao

But the developed world has lost sight of direct productive activity.

FORBES: Listen Up Bernanke, QE Is Not The Answer

Now the camera can be triggered from up to 20 meters (66 feet) away, and a direct line of sight is not necessary.

ENGADGET: Nikon D5200 to reach US photographers in late January for $900

Infra-red communication suffers the same problems, but has the additional limitation of requiring a direct line of sight between objects as anyone who has tried to operate a television remote control with someone else standing between him and the television will know.

ECONOMIST: The human body as a computer bus