采用生产能力指数法进行投资估算时正确的公式是()。
A.A
B.B
C.C
D.D
参考答案:A
麻疹传染性最强时期为()
A.潜伏期
B.前驱期
C.出疹期
D.恢复期
E.发热二周内
纤维不存在()
A.Bundles of partially lignified fibres with crystal sheaths
B.Numerous colourless single fibres, often whole with narrow lumen
C.Parenchymatous cells,fibres,and vessels
D.Starch granules present,fibres and sclereids absent
E.Fibres with crystal sheath containing calcium oxalate prisms