1.   As the lettuce gets older, the leaves become more bitter.

2.   He became very bitter and cursed the medical profession.

3.   The conflict between practical and idealist politics had become too bitter for it to be abandoned on the collapse of the Labour Government.

4.   And some nurses are becoming bitter.

5.   And that race had become increasingly bitter.

6.   And yet he never became bitter.

7.   As soon as it resumes growth next spring, it will send up flower stalks, and when it does, the leaves will become bitter.

8.   Before he left the camp, Clinton urged the assembled group of refugees not to become bitter.

9.   Before Kennan, the league was mostly unresponsive to the complaints of the assistants, who then became bitter about their situation.

10.   After that, local burdock becomes slightly bitter.