It’s not firsthand information.那不是第一手资料。I learned the news about her mother's illness firsthand from Lena.我直接从丽娜那里了解到她母亲生病的消息.School trips give children firsthand experience not available in the classroom.学校组织的出游能让孩...
妈妈,我们谈话时你不必陪着.Mommy, you don't need to stay while we talk.尽管西比斯大发牢骚，但妈妈不会放她一马。Though Sybbis complained bitterly, Mama would not let up on her.她匆匆写了个便条告诉妈妈她已外出。She scribbled a note to tell Mum she'dgone out....
心皮是由大孢子叶两边愈合进化而来的.It has evolved by fusion of the two edges of the megasporophyll.孢子异型:指植物产生两种大小不同的孢子: 小孢子和大孢子.Heterospory The production of two different sizes of spore: microspores and megaspores.通常较大的大孢子含有更多的贮藏养料.The ...