搜题请搜索小程序“爱下问搜题”
问题 选择题

在探究“绿叶在光下制造有机物”的实验中，先把盆栽天竺葵放在黑暗处一昼夜，目的是让叶片[ ]

A．合成淀粉    

B．将淀粉运走耗尽    

C．产生二氧化碳    

D．产生氧气

答案

答案：B

完形填空

In National Museum of Natural History in Washington, D.C., visitors have a rare chance to enjoy a world filled with hundreds of living butterflies. It’s an e  小题1: exhibition.

It p 小题2:a close look at butterflies. Dan Babbitt,  one of the l 小题3: of the museum says visitors can get very close to the butterflies to learn about their i小题4:   .“Our purpose is to c小题5:  people to the natural world. We have found that using animals and insects is an amazing way to do that.” Babbitt says butterflies are important to the e  小题6: for several reasons.

“One big reason is because of pollination（授粉）. They will t 小题7:   from flower to flower, taking pollen(花粉) from one flower to another. So we won’t have a number of fruit that we like to eat w  小题8: butterflies.”

“We have butterflies from all over the world” he says. “And have already s 小题9:  about 5,000 or so different kinds.” He a  小题10:  that the museum’s goal for the next five years is to let more people learn more about butterflies .
查看答案
多项选择题

海绵状血管瘤在CT和MRI上的表现特点有（）

 

A.可发生在脑外或脑内

B.有明显占位效应

C.可合并出血

D.常伴钙化

E.在MRI的T2加权像上常有一低信号环
查看答案