The careful use of lecture videos could help people study more efficiently（高效地）, say researchers at the University of California, Los Angeles （UCLA）.
According to a new study, watching lecture videos at twice the normal speed has almost no bad effect on learning. Even better, watching lecture videos at an increased speed more than once may even lead to improved learning and higher test scores compared to watching once at normal speed.
The study, done by UCLA's Department of Psychology, put students into groups and asked them to watch lecture videos at different speeds without taking notes. The students then took tests based on the video content.
The test results showed little difference in scores between students who watched the videos at normal speed and those who watched at up to double speed—meaning students could halve（减半）their study time with little effect on learning.
But students shouldn't speed up too much—because students who watched the videos at two-and-a-half times the normal speed had lower test results.
It was also found that watching the videos twice at double speed—both one week before the test and again immediately before it—produced higher test scores compared to students who watched the videos just once at normal speed.
During the COVID-19 pandemic, many countries have used some types of remote（远程的）learning, including video lessons. And while students and teachers have worried about the effects of remote learning, the UCLA study suggests that, if used the right way, video lectures could actually help make studying more efficient.
It may improve learning.
B . It may improve reading skills.
C . It may lead to the best test result.
