伞形科植物白芷的根因产地不同分为杭白芷和川白芷。（）
参考答案：错
To deal with the global financial crisis, China ______ the international community to help developing
countries.
A. called on
B. called up
C. called in
D. called for
瓷全冠的优势有（）。
A.不导热、电
B.生物相容性好
C.色泽稳定
D.强度高、脆性小
E.模拟自然牙逼真
