--- Many trees            around our school last spring.

---The more trees, the better.

A．were planting

B．planted

C．were planted

D．are planted

光滑面菌斑属于（）

A.龈上菌斑

B.龈下菌斑

C.附着菌斑

D.非附着菌斑

E.获得性菌斑