The country has already sent up three unmanned spacecraft，the most recent ________ at the end of last March.
A．has been launched B．having been launched
C．being launched D．to be launched
________ the program，they have to stay there for another two weeks.
A．Not completing B．Not completed
C．Not having completed D．Having not completed
The news of ________ greatly made us surprised a lot as he was indeed very excellent.
A．not his having elected B．not his being elected
C．his not being elected D．his not having elected
—They are quiet，aren't they?
—Yes.They are accustomed ________ at meals.
A．to talk B．to not talk
C．to talking D．to not talking
________ the meeting himself gave them a great deal of encouragement.
A．The president will attend
B．The president to attend
C．The president attended
D．The president's attending
The flu is believed ________ by viruses that like to reproduce in the cell inside the human nose and throat.
A．causing B．being caused
C．to be caused D．to have caused
