A.Cell phone use is dangerous.

B.Cell phone use causes cancer.

C.The human brain is an electromagnetic field.

D.There are about 5 billion cell phone users in the world right now.

2.Doctor Volkow was astonished because ______.

A.her research has shed light on her understanding of cell phone

B.she found that cell phone exposure is harmful to human brain

C.she found that using a cell phone for about 50 minutes could influence or change brain activity

D.human brain is not responsive to electromagnetic radiation

3.According to the passage， cell phones were launched _______.

A. in the late 1970s B. between 1980 and 1985

B. in the late 1980s D. in the early 1990s

4. What does the word “that” stand for in the second paragraph？

A.Brain activity.

B. Her research findings.

C.The fact that cell phone use may cause cancer.

D. Her research progress.

5.Which of the following is an appropriate title for this passage？

A.Cell Phone Radiation： Is It Harmful？

B.Cell Phone Radiati0n： Is It Useful？

C.Cell Phone Radiation： Is It Healthy？

D.Cell Phone Radiation： Is It Weak？

Passage 2