I bought a sweater for only 50 yuan yesterday; it was a real        .

Health problems are closely connected with bad eating habits and a ____ of exercise. 

—How many ________ are there on the table?  —There are five. 

 Tourists can have a better view of the sea and the island from their _____ on the top of the temple on the mountain.

The invention of the typewriter was a great_______  to communication and printing.