Many lessons are now available online，from ______ students can choose for free．（　　）

If you look at all sides of the situation，you'll find probably a solution that _______ everyone．（　　）

They decide to have more workers for the project ______ it won't be delayed．（　　）

Building such a bridge over the bay was ______，but the local government made it within two years．（　　）

It is not a problem ______ we can win the battle；it's just a matter of time．（　　）