单项选择题

______ complex organic catalysts originating in living cells.

A．Enzymes are
B．Enzymes while they
C．Enzymes
D．Enzymes which are
<上一题 目录 下一题>
热门 试题

单项选择题
Work in parapsychology, ______, has attracted a rel atively small number of scientists.
A．is a very controversial field
B．a field very controversial which
C．which a very controversial field is
D．a very controversial field
单项选择题
We need help with the fourth problem; it ______ us.
A．persists
B．permeates
C．perplexes
D．perturbs
相关试题