Look before you leap! You have to ______the costs of the new system against the benefits it will bring.
—You have no idea how to solve this math problem. —You should try to think about which principle can _______ it.
The tall good-looking guy was thought to be the owner of a large company _______ in fact he was as poor as a church mouse.
Being quick-minded and good at communicating, the young man was appointed to address the tough problem _______ the company.
To be an excellent lecturer, you must be a clear speaker, with a strong and pleasing voice that is fully under your _______.
With some physical training in the morning,even after a couple of days,you will feel ______,and in the long term,you will benefit greatly from your perseverance.