1.  A certain level of corruption is tolerated as part of the grease that oils the wheels of the republic.

2.  At a certain level, people are beyond that.

3.  But human negotiators are slow, and can cope with problems only up to a certain level of complexity.

4.  For many parents, of course, those words produce a certain level of dread.

5.  Grant-aid was available, but only in houses with rates below a certain level.

6.  If you want to get the most out of life you need to maintain a certain level of muscular stamina.

7.  In order for most of us to become self-motivated learners, we need to reach a certain level of success.

8.  It would also test whether a certain level of complexity birthed self-sustainability.

9.  Judges expect a certain level of competence, so staging a little-girl-lost act in court will do no good whatsoever.

10.  Many invertebrates, such as crayfish, can not survive without a certain level of calcium, and are completely absent.