In the past few years, traffic problems （become) ________ more and more serious.

Now scientists have found in the past few years ______.A．the exposure of DNA to the public

根据下列材料，请回答题Electronic MailDuring the past few years， scientists all over the wor

The past few years have given way to a heated debate about whether downloading free online

In the past few years, it has been a trend for Chinese universities to build new campuses,

In the past few years the workers have______ a lot of suggestions, some of which are being

AIDS is said() have been the biggest health challenge to both men and women in that area over the past few years.