单项选择题
A．be treated B．treating C．being treated D．treat
Most environmental problems exist because adequate meas...
单项选择题Most environmental problems exist because adequate measures for preventing them（）in the past.
A．was not taken B．were not taken C．didn't take D．haven't taken
Since the introduction of the new technique, the produc...
单项选择题Since the introduction of the new technique, the production cost（）greatly.
A．reduces B．has been reduced C．is reducing D．is reduced
I'll take down your name and address in case you（）as a ...
单项选择题I'll take down your name and address in case you（）as a witness.
A．are needed B．have needed C．need D．were needed
