Great as Newton was, many of his ideas _______ today and are being modified by the work of scientists of our time.
#102473
A
are to challenge
B
may be challenged
C
have been challenged
D
are challenging
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The milk must be preserved at this temperature until it ____.
#101024
A
will process
B
is processed
C
has processed
D
had been processed
 Don’t leave the chairs about, or you may ______ them at night.
#99797
A
take over
B
turn over
C
come over
D
trip over