题目

71.The man spent much of his childhood_________(observe) birds in the wild. 72.My friend was down with the flu,and_______（因此）couldn't come to the party. 73.He w_______to her so that no one else could hear. 74.I'm full up.I couldn't eat another m________. 75.There are many______________（方法）to improving students's writing ability. 答案：71.observing      72.therefore                     73.whispered             74.mouthful               75.approaches Low-carbon lifestyle is of great benefit to improve the world environment, but the problem is difficult to _________． A．solve B．be solved C．solve with D．solving