He tried his best to solve the problem, _____ difficult it was.
| A．however | B．no matter | C．whatever | D．although |
There is a car ___ the house.And the driver is sitting ___ the car.
A. in front of,,, in front of B, in front of … in the front of
C. in the front of… in the front of D. in the front of… in the front of
They haven't decided ___ they will go for a drive on Sunday or not.
| A．that | B．how | C．which | D．whether |
___ new products have been successfully made in the factory.
| A．A great deal of | B．A number of | C．The number of | D．A great amount of |
Either you or I __ to blame for this.
| A．am | B．is | C．are | D．be |
--Was the driving pleasant when you vocationed in Mexico last summer?
----No, it ___ for four days when we arrived, so that the roads were very muddy.
| A．was raining | B．had been raining | C．would be raining | D．have rained |