目前应用最广泛的种植材料是
A.生物活性陶瓷
B.生物降解陶瓷
C.钛及钛合金
D.复合材料
E.高分子材料
参考答案:C
A talk on developments in science and technology _______ in the school hall next week. [ ]
A. given
B. will be given
C. has been given
D. gives
催化主风机额定电压是3000V。