By serving others,a person focuses on someone other than himself or herself,_______can be very eye-opening and rewarding.
After months of voyage, Columbus arrived in ______ later proved a new continent.
The idea has been widely accepted______Beijing Opera should be added to the basic education in China.
I have no doubt that he will pass the exam, but I still think there is something about _____ he has really got everything ready.
_____ puzzles me most is that I don’t know ______ the difference between the two lies.