I think the talk given by the old scientist is ______ worth ______

Mr. Wang is very strict _______ his students.

to the measures ______ by the localgovernment , the polluted river is becoming clearer and clearer and fish havebegun to show up in it

The chief reason for the population growth isn’tso much a rise in birth rates ________ a fall in death rates as a result ofimprovements in medical care.

The notice came around two in the afternoon_______ the meeting would be postponed