PDF chapter test TRY NOW

Choose the correct verb forms according to the tense given in the brackets:  
 
1. There is nothing which __________ (add) so much to the beauty of the countryside as water. (Simple present) -
 
2. The menace of soil erosion to the continuance of successful agriculture is an __________ (alarm) one. (Present Continuous) -
 
3. Man has through the ages ___________ (seek) in vain for an imaginary elixir of life. (Present Perfect) -