单项选择（每题1分）We must think twice _____ we make the final decision.

“You can’t have your football back ____ you promise not to kick it at my dog again,” the woman said firmly.

Make decisions right away, ______ you’ll miss a golden chance.

_______ the calculation is right, scientists can never be sure that they have included all variables and modeled them accurately. 

A small car is big enough for a family of three ____ you need more space for baggage.