—Is there anything wrong, Bob? You look sad.—Oh, nothing much. In fact , I ____ of my friends back home.
You have to wear a helmet and a life jacket for protection, just ___ you fall into the water.
Wuhan lies _____ the Changjiang River and the Han River meets.
nation uses nuclear weapons will engage the whole world in war.
You are asked to attend the meeting ______ in the hall this weekend.
When ____ to danger and conflict, men tend to increase blood pressure, ____ nervous or anxious.