Time is life; therefore, waste your time and waste your life, ______ master your time and master your life.
| A．and | B．for | C．so | D．or |
He tried his best to solve the problem，_____difficult it was.
A however B. no matter C. whatever D. although
Parents should take seriously their children's requests for sunglasses ____eye protection is necessary in sunny weather.
A because B. though C. unless D. if
Roses need special care ____they can live through winter.
A because B. so that C. even if D. as
— Mrs Green is angry with Mary. It seems ______ she is going to call her mother.
— Right, let’s persuade Mary to give up now.
A as if B as long as C even if D in order that
He shut the window with such force _____ the glass broke.
A which B that C as D if