The new research team was led by the ________engineer.
A. main B. major C. chief D. primary
—Will you come?
—________you promise not to invite Mary.
A. As if B. If only C. Only if D. Even if
They ________ to enter the building by the back door; however, the front door was locked.
A. are supposed B. aren’t supposed C. weren’t supposed D. were supposed
He _________his friend in the crowd at the first sight and called out his name.
A. spotted B. watched C. observed D. glared
Used to TV shows, ________ everything is quick and entertaining, many people do not have the patience to read a book that requires thinking．
A．which B．what C．where D．when
According to the government, the new tax law will not ________until next month.
A. take effect B. bring into effect C. carry into effect D. be for effect
