一次施工可同时处理几个性质相近油层的压裂工艺技术为（）压裂。
A、分层
B、投球
C、暂堵剂
D、限流
参考答案：D
What does the man hear [A] He hears someone singing. [B] He hears someone calling him. [C] He hears someone calling the woman.
被保护的野生动物种类有哪些？
