4. lease: allotted time.  date: duration.

7. fair . . . fair: beautiful thing . . . beauty.  sometime: in the course of time.

8. untrimm'd: stripped of beautiful ornament.

10. fair: beauty.  thou ow'st: you own.

12. lines: i.e., lines of poetry.  to time thou growest: to time you become engrafted (so that you are immortal).