暑假適合考雅思嗎?
In years with hotter weather pupils are likely to perform less well in exams, says a major study from researchers at Harvard and other US universities.
There is a "significant" link between higher temperatures and lower school achievement, say economic researchers.
An analysis of test scores of 10 million US secondary school students over 13 years shows hot weather has a negative impact on results.
The study says a practical response could be to use more air conditioning.
Students taking exams in a summer heat wave might have always complained that they were hampered by the sweltering weather.