ALBANY，New York—Students who rely on working at night to improve their
grades might want to sleep on that strategy: A new survey in the US says those who never study all night have slightly higher grades than those who do.
A survey of 120 students at St.Lawrence University found that students who had never pulled an all­nighter on average had higher grades than those who had. The survey found those who did not study through the night had a grade point average of 3.2 compared to 2.95 for those who did.
The study, by assistant professor of psychology Pamela Thacher, is to be included in the January issue of Behavioral Sleep Medicine.
“It's not a big difference，but it's pretty striking, ” Thacher said, “I am primarily a sleep researcher and I know nobody thinks clearly at 4∶00 in the morning. You think you can do，but you can't.”
Many college students, of course, have inadequate or irregular sleep, for reasons ranging from excessive caffeine to poor time management.
“A lot of students were under the impression that all­nighters were a very useful tool for accomplishing work, and that caffeine intake was very useful in meeting deadlines and stuff like that, ”said Mr Chatani, who had a 3.4 grade point average last term.
Dr Howard Weiss, a physician at St.Peter's Sleep Center in Albany, said the study results made sense.
“Certainly that data is out there showing that short sleep duration absolutely interferes with concentration and performance on objective testing, ”he said.
“Some night owls do get good grades, of course，which may be explained by circadian (昼夜节律的，生理节奏的) rhythms, ”Weiss said, “Some people have different 24­hour body clocks from others, and may do better depending on classes and testing time.”
63.The purpose of the passage is to tell us 　　　　
A. the bad effects of pulling an all­nighter
B. pulling an all­nighter leads to sleep problems
C. Thacher's doubt about all­nighters
D. all­nighters influence students' grades
64. According to Thacher's study，around 4 o'clock in the morning is a time when 　　　　.
A. one can think more clearly
B. one has his/her best memory
C. one can't learn efficiently
D. one's brain falls into a period of deep sleep
65.What can we know from Dr Howard Weiss' words？
A. Thacher's study is not convincing enough.
B. He believes in Thacher's study.
C. Thacher's study makes no sense.
D. Thacher should take exceptions into consideration.