______ the students in our class is 50 and _______ them study very hard.
Green products are becoming more and more popular because they are environmentally ______.
Nobody could believe what Chloe says because she is ______ changing her mind.
Don't ______.You will ______ new customs and different ways of thinking.
It______ a calm head to find the best solution to such a difficult problem within a short time.
By the end of 2007,about half a million people had flooded into the city,______ up around 10 percent of its total population.