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

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

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

If only I______hard in the past few months! But I didnt work hard enough and failed the ma

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

Working hours in the United States ____________over the past 20 years.A. have increased