1.Scientists have responded by noting that hungry bears may be congregating (聚集) around human settlements, leading to the illusion(错觉) that populations are ________ (high) than they actually are.

　　答：higher

　　空格后的than提示我们空格处用形容词的比较级higher。

　　2.According to a review of evidence in a medical journal, runners live three years ________ (long) than non-runners.

　　答：longer

　　空格后的than提示我们空格处用形容词的比较级longer。

　　3.While running regularly can’t make you live forever, the review says it is more effective at lengthening life ________ walking, cycling or swimming.

　　答：than

　　句意：虽然定期跑步不能让你永远活下去，但该评论称，与步行、骑自行车或游泳相比，跑步在延长寿命方面更有效。

　　根据句意可知，空格处应该填“than”意为“比…”。

　　4.Even ________ (bad), the amount of fast food that people eat goes up.

　　答：worse

　　暗含在语义中的比较级“比这更糟糕的”，even 用在比较级前，加强语气，表程度。

　　5. After our plane landed, we went to the hotel. We had made our reservation six months ________ (early), but the man at the front desk said there had been a mistake.

　　答：earlier

　　句意：飞机降落后，我们去了酒店。我们六个月前就预订了房间，但前台的人说有错误。

　　时间段+ earlier，表示多久之前。

　　6. It might have made it a little ________ (hard) for everybody because it meant they had to turn around.

　　答：harder

　　hard有两种词性，形容词和副词。根据题干中的make+ n. +adj. 可知，空格处需要填形容词。a little 用在比较级前，加强语气，表程度。

　　7.The teacher replied, You tasted the water. I tasted the girl. The water was simply the container for an act of kindness and love. Nothing could be ________ (sweet).

　　答：sweeter

　　句意：老师回答说：“你尝到了水的味道。我尝到了女孩的味道。水只是一个用来表达善意和爱的容器。没有比这更甜的了。

　　根据句意可知空格处应该填形容词的比较级sweeter，更甜的。

　　8.He was very tired after doing this for a whole day, but he felt very happy since the crop did “grow” ________ (high).

　　答：higher

　　句意：做了一整天之后，他非常累，但他感到非常高兴，因为作物确实“长”得更高了。

　　根据句意可知空格处应该填形容词的比较级higher，更高的。

　　9.We decided it was time for some action and what ________ (good) than to ride on a piece of history!

　　答：better

　　空格后的than提示我们空格处用形容词的比较级better，更好的。

　　10.Oranges: Orange trees are more ________ decoration; they are a symbol of good fortune and wealth.

　　答：than

　　句意：橘子树不仅仅是装饰;它们是好运和财富的象征。

　　more than 为固定搭配，意为“不仅仅是”。