阿摩線上測驗
1. Vaccines help teach your pet’s _____ system how to recognize and fight off certain disease-causing agents.
(A) digestive
(B) nervous
(C) respiratory
(D) immune
答案：登入後查看
統計： A(0), B(0), C(0), D(12), E(0) #3578070
統計： A(0), B(0), C(0), D(12), E(0) #3578070
