The checkups were a good idea, but she needn't have panicked.检查是个不错的主意, 但大可不必惊慌.You needn’t feel any guilt about me.你用不着因为我而內疚。You needn't worry...你不必担心。"I'll put the key in the window." — "You needn'...
他现在把变量叫做流,变量的变化率叫做流数.He now called a varrable quantity a fluent and its rate of change , the fluxion.于是, 在正常点火时,叶片温度的变化率约为30度/秒.Thus, during a normal light-up the temperature charge rate on the blade is about 30 degrees/...