Chance and tendency chance to; happen to; tend to
I chanced to overhear part of their conversation = heard by chance.
She happened to notice the number-plate = noticed by chance.
He tends to be nervous, doesn’t he? = often is
One day, as you are washing1 your hands, you happen to glance2 into the mirror over the basin and a sudden doubt will flash3 across your mind: ‘Is4 that really me?’ ‘What am I doing5 here?’ ‘Who am6 I?’ Each one of us is so completely cut off7 from everyone else. How do you know8 you are reading9 a book? The whole thing may be10 an illusion. How do you know11 that red is12 red? The color could appear13 blue in everyone else’s eyes. A similar doubt, differently expressed, is14 inherent in the well-known question: ‘A tree that has fallen15 in the forest, far from the nearest man – when it fell,16 did it make17 any noise?’
(Magnus Pyke, The Boundaries of Science)
Be as main verb: 4, 6, 12, 14. Be as aux. progressive: 1, 5, 9. Be as aux. passive: 7. Have as aux. perfect: 15. Do as aux. present: 8, 11. Do as aux. past: 17. Modal aux: 3, 10, 13. VG with catenative happen to: 2.
