问题
选择题
The world is changing fast.I strongly believe that one will easily fall behind _______ he keeps on learning.
A．unless
B．if
C．when
D．as
答案
A
本题考查连词用法。根据句意，如果不学习很容易落下；所以选A项。
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The world is changing fast.I strongly believe that one will easily fall behind _______ he keeps on learning.
A．unless
B．if
C．when
D．as
A
本题考查连词用法。根据句意，如果不学习很容易落下；所以选A项。