1 . Sudden changes in water temperature may ________ the deaths of aquatic animals and plants. A . lead in B . put out C . come up with D . result in 2.______ USA is the most diverse country in geography and climate. A. an B .the C . a D . no article 3. Some of the collapsed buildings and houses ________ by the government so far. A .had been repaired B. have repaired C . have been repaired D . had repaired 4 . The Earth will become worse and worse if humans ______ action right now. A . don't take B . cannot take C .couldn't take D.didn't take 5 . People _______ herbicides to kill weeds along the river banks, but now they don't. A . aren't used to using B . used to use C. are used to using D .didn't use to use 6 .there _______ a severe drought before the heavy rain last night. A .had been B .was C . has been D.will be (giup mi kvoi )