_______ the calculation is right, scientists can never be sure that they have included all variables and modeled them accurately.
| A．Even if | B． As far as | C．If only | D． So long as |
-- Mr Smith ,What shall we do next?
-- Let students ___________for discussion.
| A．swept the floor | B．build the floor | C．open the floor | D．took the floor |
--I'll be waiting for you at home.
-- ______ I were busy and couldn't come?
| A．What if | B．What when | C．How if | D．How when |
His mother could do nothing but _______ for the doctor to arrive.
| A．to wait | B．waiting | C．waited | D．wait |
We still have a long way to go to solve all the problems _____________the Yangtze River.
| A．regardless of | B．in regard to | C．in search of | D．instead of |
-- Do you think we should accept the offer?
-- Yes,we should, we ________ such bad luck up till now, and time _______ out.
| A．have had; has been run | B．had; is using up |
| C．have; is running | D．have had; is running |