问题
选择题
While typing, Helen has a habit of stopping ______ to give her long and flowing hair a smooth.
A．now and then
B．over and over
C．up and down
D．here and there
答案
Ａ
词义辨析。Ａ时而不时；Ｂ一再；Ｃ上上下下；Ｄ到处。结合句意可知Ａ正确。句意：在打字的时候，Ｈｅｌｅｎ有时而不时停下来的习惯，让长长的头发顺下来。