四则混合运算指的是哪四个

简介：The two women and several female mercenaries had a lot of fun playing with the small dinosaurs. However, the male mercenaries were not that fun. They just jumped on the backs of some adult dinosaurs and sat there, blowing the cool breeze. The adult dinosaurs also Ignore them, as if they are just a flea on your back, and don't care at all.