橡胶塑炼程度越深,橡胶大分子链遭受破坏越大,降低了制品的耐老化性能。
参考答案:对
The boy was sitting on the floor ______ by toys. [ ]
A. fsurrounded
B. surrounding
C. surroundings
D. surround
肛门坐浴治疗的水温要求是()
A.39~41℃
B.37~39℃
C.41~43℃
D.35~37℃
E.43~46℃