By increasing or lessening the hours of darkness in each day, the scientists have been able to turn plant growth off and on like an electricswitch.
用增加和减少每天黑暗小时数的方法，科学家已经能够控制植物生长，如同控制一个电器开关。
2
At the bottom of the stairs my hand met an electricswitch. I turned it, and a great electrolier of twelve red globes flooded the cellar with a red light.