“螟蛉有子，蜾赢负之”(《诗经·小雅·小宛》) ，这句话含有的种间关系是[ ]
A．竞争
B．互利共生
C．捕食
D．寄生
答案：C
________, the northerners like noodles while the southerners are fond of rice in China. [ ]
A. In common
B. In general
C. In total
D. In return
钢材变形的原因主要有哪几种？常用的矫正方法又有哪些？
