____ with what the students had done, the teacher praised them highly.

With the word "PM2.5"______ heard and seen in our life, people become more and more concerned about air pollution.

Despite the fact that all three teams ________ different approaches to the problem, they were all immediate successes．

The manager was absent because of illness； ______，the meeting was put off until tomorrow.

The time and effort he has devoted during the past few years____ trees in that remote area is now considered to be of great value．