30.According to the passage,the invention of the visible-light microscope allowed scientists to (A)see viruses directly(B)develop the electron microsc...
Question 20-28Under certain circumstance the human body must cope with gases at greater-than-normal atmospheric pressure.For example,gas pressures inc...
语法 (Page 174)1.Some snakes lay eggs,but others _____ birth to live offspring.(A)give(B)giving(C)they give(D)to have given2.Because it was so closely r...
Question 20-30Before the mid-nineteenth century,people in the United States ate most foods only in season.Drying,smoking,and salting could preserve me...
Question 9-19Birds that feed in flocks commonly retire together into roosts.The reasons for roosting communally are not always obvious,but there are s...
阅读(Page 168-170)Question 1-8With Robert Laurent and William Zorach,direct carving enters into the story of modern sculpture in the United States.Direc...
14.Written to be performed on a _____,Thornton Wilder's play Our Town depicts life in a small New England community.(A)stage scenery of bare(B)bar...
语法(Page 167)B1.The ponderosa pine is _____ of most of the timber used by forest product firms in the Black Hills of South Dakota.(A)the source(B)as so...
39.Which of the following is NOT mentioned as an adaptation of large desert animals?(A)Variation in body temperatures(B)Eating while dehydrated(C)Drin...
Question 29-39Large animals that inhabit the desert have evolved a number of adaptations for reducing the effects of extreme heat.One adaptation is to...