is very strict with others, but heis always blind _____ his own shortcomings

Chemical pollution will bring about a threat to agriculture and food chain, and ________ to human health[ ]

Sam _______ some knowledge of the computer just by watching others working on it. [ ]

I don’t think one country can solve the problem of pollution alone, _______

I received a number of ________, but ________ of themis valuable to me.