她以前不常锻炼，但自从加入跑步俱乐部后每周都跑三次。
She used not to exercise much, but since joining the running club she runs three times a week.
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used英 /juːzd/|美 /juzd/|英 /juːst/|美 /just/
not英 /nɒt/|美 /nɑt/
to英 /tuː/|美 /tu/|英 /tə/|美 /tə/
解释
used not to 否定过去的习惯频率，but 从句交代改变的原因和新常态。
She used not to exercise much, but since joining the running club she runs three times a week.
used not to 否定过去的习惯频率，but 从句交代改变的原因和新常态。