上皮基膜的功能有
A. 支持作用
B. 连接作用
C. 半透膜作用
D. 引导上皮细胞移动
E. 影响细胞的分化
钢筋弯曲成型时, 弯起钢筋的弯折位置允许偏差为( )。
A. ±5mm
B. ±10mm
C. ±15mm
D. ±20mm
条形基础底板中,在两向受力钢筋交接处的网状部位,分布钢筋与同向受力钢筋的构造搭接长度为()
A. 150mm
B. 100mm
C. 75mm
D. 50mm
Skim the first paragraph of the reading passage, and look at the subheads. How might feathers help with each function? Note your ideas and discuss them with a partner. Then check your ideas as you read the passage.