（）are experienced in temperate latitudes during warn summer

If you are like most people,your intelligence varies from season to season．You are probably a lot sharper in the spring than you are at any other time of the year．A noted scientist,Ellsworth Huntington(1876-1947),concluded from other men's work and his own among peoples in different climates that climate and temperature have a definite effect on our mental abilities.
He found that cool weather is much more favorable for creative thinking than is summer heat．This does not mean that all people are less intelligent in the summer than they are during the rest of the year．It does mean,however,that the mental abilities of large numbers of people tend to be lowest in the summer.
Spring appears to be the best period of the year for thinking．One reason may be that in the spring man's mental abilities are affected by the same factors that bring about great changes in all nature.
Fall is the next-best season,then winter．As for summer,it seems to be a good time to take a long vacation from thinking!

According to the passage,any vacations from thinking should be taken__.

A.several times throughout the year
B.during spring and fall
C.during the summer
D.as seldom as possible

资料：Did your child's brain shrink last summer? Probably not, but it may have shifted into reverse, according to a study by Dr. Harris Cooper, professor of psychology at the University of Missouri-Columbia. The study found that when students return to school after a long summer vacation, they've lost one to three months worth of learning.
The decline is more detrimental for math than it is for reading. "All students lose math skills," says Cooper. It may be because community and home environments give kids more opportunities to practice reading than math. The study also found that income has an impact on how much a student loses or gains in reading. Middle-class children actually gained in reading over the summer, while lower-income students experienced losses. Cooper attributes this to the enrichment activities that many middle-class kids participate in over the summer, such as camp and trips.
Your kids don't have to spend the summer stuck in reverse. "Parents can help their kids retain educational skills," says Cooper. He suggests the following five tips to kick off a learning-filled summer.
1. Keep lots of books around and make regular trips to the library. Most libraries schedule special summer events for kids. Sign up your family!
2. Think about what your kids may be learning next year when you plan the family vacation. Talk with teachers to find out what they'll be covering in class. If it's a unit on the civil war for example, you may want to schedule a visit to Gettysburg. If it's geology, visit a national park.
3. Keep math in mind. Since kids lose more math skills than anything else over the summer, try to do some special planning to find math-related activities. For example, if you can't decide whether to sign your child up for "Shakespeare's Theater" or "Math Magic" at the local community center, go with the math.
4. Consider summer school or tutoring. Struggling kids can get a lot of different kinds of help from these programs. Summer school can also enrich and accelerate learning in areas where kids show a special interest.
5. Call the curriculum coordinator in your child's school district, visit the school board office, or contact the schools of education at local colleges and universities to find out what educational programs will be offered in your area over the summer.
Remember to keep it fun! You don't want to sour your kids on learning during the summer break.

How dose income affect a student’s loses or gains in summer learning? （ ）

A.Lower-income children experienced lose in math over the summer
B.Middle-class children gained in learning over the summer
C.Lower-income children gained in math over the summer
D.Middle-class children suffered lose in math over the summer