{x+y=55x=2y−
农业上用射线或药物处理农作物种子,获得新品种的原理是射线或药物( )
遗传学上的密码子是指( )
In many parts of China, people _______ the custom of "biting the spring" on the first day of Start of Spring, with spring pancakes and spring rolls eaten.
--Where is my watch? I ________ find it.
--Don't worry. It must be somewhere in your room.