【单选题】_______, Jack couldn’t get the door open. He had to dial 119.
【简答题】消除系统误差的方法主要有 、 、 、 等。
【单选题】患者张某,45岁,输血10ml左右出现头痛、四肢麻木、腰背酸痛,伴寒战、高热、呼吸急促等症状。下列措施不正确的是
【简答题】Try as he might, he could not find a job.
【单选题】Try____he might, he couldn't solve the problem.
【单选题】Try _______he might , he couldn’t get out of difficulty .
【简答题】生成树构成的三个步骤是:1. 选择( ),2.选择( ),3.选择( )。