按岩石的成因分类,地壳上的岩石共分为()3大类。
A、化学岩、碎屑岩和生物岩
B、岩浆岩、沉积岩和变质岩
C、岩浆岩、陆源岩和变质岩
D、岩浆岩、风化岩和变质岩
参考答案:B
用动词的适当形式填空。
1. She likes musicians who (write) their own lyrics.
2. I prefer singing to _______(dance).
3. The boy _______(see) to play basketball just now.
4. Would you mind my_______(close) the window?
5. Be sure (see) this exhibition at the Lido Gallery.
关于α-螺旋正确的是()。
A、螺旋中每3.6个氨基酸残基为一周
B、为右手螺旋结构
C、两螺旋之间借二硫键维持其稳定
D、氨基酸侧链R基团分布在螺旋外侧