optimistic pessimist
Senior Member
- Joined
- Jan 1, 2008
- Member Type
- Native Language
- Japanese
- Home Country
- Japan
- Current Location
- Japan
Hi everyone!
I'm reading an article about the biological clock.
"In the early eighteenth century, the French astronomer Jean-Jacques de Mairan was struck by the way the mimosa plants on his windowsill raised their leaves toward the sun at the same time every day. An effect of the light? Mairan placed the mimosas in a dark cellar, but the leaves kept right on unfuring every morning and closing back up every evening....
I'd like to ask about the words in bold font. Why is it not just "closing" or "closing back"? What does "up" mean here?
Thank you
OP
I'm reading an article about the biological clock.
"In the early eighteenth century, the French astronomer Jean-Jacques de Mairan was struck by the way the mimosa plants on his windowsill raised their leaves toward the sun at the same time every day. An effect of the light? Mairan placed the mimosas in a dark cellar, but the leaves kept right on unfuring every morning and closing back up every evening....
I'd like to ask about the words in bold font. Why is it not just "closing" or "closing back"? What does "up" mean here?
Thank you
OP