–It’s too late to go to the football match now; ______,it’s being to rain. 

Chemical pollution will bring about a threat to agriculture and food chain, andto human health.

I can’t say I’m the best. I have only _________ made more efforts than others.

 ----What do you think of the film we saw last night? ----I feel ______ that the film is well worth seeing once more.

The poor boy couldn't work the problem out. He wasn't ____ clever.