A：该实验能够证明DNA是遗传物质
B：侵染所需的原料、ATP、酶、场所等条件均由细菌提供
C：为确认何种物质注入细菌体内，可用32P、35S共同标记一组噬菌体的DNA和蛋白质
D：连续培养噬菌体n代，则含母链的DNA应占子代DNA总数的1/2n-1
给划线的字选择正确的读音。
①允许____
A．nà
②云彩____
B．yǔn
③呐喊____
C．ná
④拿走____
D．yún
nervous visited by clouds went sky had saw
Dear Simon,
How are you? Last week I ____ to Xi'an. It's in the northwest of China. I went there ____ plane. The plane took us to the ____. First, I was a little ____. Then I looked out of the window.
The plane was above the ____. I ____ some mountains below. I ____ lunch on the plane. Later I arrived in Xi'an. I ____ many interesting places. The trip was great!
Love,
Daming
作为公民，在做好本职工作的同时，还要热心公益事业，承担起关爱社会的责任。下列属于参加社会公益活动的是（ ）①参加学校组织的“青春飞扬——校园歌手”竞选活动②参加义务植树③义务向居民宣传防火的知识④无偿资助贫困山区的孩子上学
