Apples are usually sold by ________ weight and eggs are sometimes sold by ________ dozen.
—People say your little brother has been admitted into QinghuaUniversity. —Yes. Never ________ he could achieve so much success.
________ reducing pullution, man should pay more attention to conserving energy.
I enjoyed very much the three years ______ it had taken me to study English at school.
Being examined twice a year, whether it is a car or a bus or a truck, is the rule that every driver _____ obey in this city.
On farewell party the foreign teacher gratefully _________ all the helps from all the school.