信号在网络的边缘区域变得很弱。

The signal becomes very weak at the ___extremities of the network.

医生建议糖尿病患者要特别注意四肢的血液循环。

Doctors advise diabetic patients to pay special attention to blood circulation in their ___extremities.

在极寒天气里，登山者不得不采取极端措施来保暖。

In the freezing weather, the climbers had to resort to ___extreme measures to keep warm.