This problem may lead to more serious ones if ____ unsolved.
A careless joke _____ an argument between the two friends, and so far they haven’t forgiven each other.
No matter when people ______ him about their financial troubles, the lawyer is always ready with advice.
“One blue represents the economy growing. The other blue is the blue sky. That means we have to ______ development and environmental protection,” Wang Zhongbing said.
Daily practice is a good ______ in learning English. If you keep trying, you will be sure to make greater progress.
Most of us believe that there should be a(n) ______ of mutual(相互的) trust and respect between teachers and students in teaching.