金属塑性变形过程中发生孪生后，孪晶面两边的晶体位向呈现______，并且晶体是______切变的。
参考答案：对称关系；均匀
All the preparations for the task ___,and we're ready to start. [ ]
A. completed
B. complete
C. had been completed
D. have been completed
甲状旁腺素对血液中钙磷浓度的调节作用表现为
A．降低血钙浓度，升高血磷浓度B．升高血钙浓度，降低血磷浓度C．升高血钙浓度，不影响血磷浓度D．降低血钙浓度，不影响血磷浓度E．升高血钙、血磷浓度
