Achieving a high degree of proficiency in English as a foreign language is not a mysterious _____  without scientific basis.

If you don’t take away all your things from the desk, there won’t be enough_____ for my stationery.

Next week there will be a basketball match between the ________ and the ________of our school. 

The environmentalists said wild goats’ __________ on the vast grasslands was a good indication of the better environment.

Scientists have to work hard to keep _____ with modern discoveries and developments.