John, _______ university professor, is considered to be _______ success as ______ expert in the agriculture research.
. It was _____ his mother came in _____ to prepare his lessons.
. _______ has already been pointed out, grammar is not a set of dead rules.
. You should try to _____ new circumstances as quickly as you can
. ---I’ m sorry, but I didn’t mean__________ out your secret. ---But you know, letting out one’s secret means________ one’ s feelings.
. He made another wonderful discovery, _______ of great importance to science.