决定劳动供给曲线形状的因素是（ ）。

(单选题)( ), the more severe the winters are. (单选题)( ) he wanted to go out with his friends at the weekend, (单选题)Mr. Wells, together with all the members of his family, ( (单选题)Had Judy been more careful on the maths exam, she ( ) mu (单选题)Stan Lee, an outstanding comic-book writer, created plenty o (单选题)The great hall was crowded with many people, ( ) many chi (单选题)If city noises ( ) from increasing，people ( ) shout to (单选题)If you really have to leave during the meeting, you'd better (单选题)At three thousand feet, wide plains begin to appear, and the (单选题)如上所示