电控燃油系统中，燃油压力通过（）调节。 A.喷油器 B.燃油器 C.压力调节器 D.
题型：单项选择题
问题：
电控燃油系统中，燃油压力通过（）调节。
A.喷油器
B.燃油器
C.压力调节器
D.输油管
题型：单项选择题
Texting is a great way to communicate and teenagers are doing just that. New research shows that on average, teens are sending 2,000 text messages a month, and doctors say it’s causing injuries.
13-year-old Bailey Baker keeps using her thumbs, sending text messages to her friends again and again. The past March may have been her best month ever, texting 8,000 times. Now, she says she’s feeling the pain. “Just mainly back and neck problems and thumb numbness,” she says.
Baylor-Garland Dr. Jane Sadler is seeing more and more teens who simply text until it hurts. She says parents, including Bailey’s mom, have no idea how much their kids are texting. “I was thinking she was texting about 25 texts a day,” says Lisa Baker. “Wrong! We’ve uncovered a problem.” It didn’t take Dr. Sadler long to find the problem. She gave Bailey the once-over and learnt that Bailey had developed Texting Teen Tendinitis(肌腱炎)
“A lot of them report pain in their thumbs, back and neck,” says Dr. Sadler. “When we look into it 
and examine a little bit further, we see texting is the main cause of the problem.” Dr. Sadler says back pain is caused by poor posture while texting. Bailey often texts for up to 2 hours a day; that’s a lot of wear and tear on the thumbs which over time, can break down. Dr. Sadler tells over-texting teens to look into the future. “What I tell them is ‘Hey, you might be normal now, but when you are 40 or 50, you can get arthritis (关节炎).’”
Dr. Sadler recommends limiting texting to 50 a day, and keeping good posture. Dr. Sadler also says touch screens are easier on the thumbs than keyboards and hand exercises are great to build up those muscles, making it easier to text.
1. How many text messages did Bailey Baker send a day on average last month?
A. Less than 226. B. About 230. C. About 267. D. More than 300.
2. Because of texting, Bailey Baker suffers from the following problems EXCEPT ______.
A. back pain B. neck pain C. headache D. thumb numbness
3. What does the underlined part in Paragraph 3 mean?
A. She gave Bailey Baker a quick examination.
B. She solved Bailey Baker’s problem at once.
C. She gave Bailey Baker a piece of advice.
D. She let Bailey Baker send a text message again.
4. What can we conclude from Paragraph 4?
A. Teenagers won’t get hurt if they stop texting right now.
B. Poor posture while texting is the main cause of injuries.
C. Thumbs won’t ache if teens text for no more than 2 hours a day.
D. Over-texting may have a bad effect on people in the long run.