Most computer users think it necessary for their software ________ regularly．

A．to up date

B．to be updated

C．to have been up dated

D．to have updated

为避免发霉、变色、虫蛀及有效成分的分解和破坏，药材储藏前一般均需

A．极面观呈三角形，角端各有一个萌发孔
B．呈类球形或长圆形，外壁有细点状条状雕纹
C．呈球形、黄色、外壁具细刺状突起
D．呈球形或椭圆形，表面有似网状雕纹
E．花粉粒少见，呈圆球形，外壁近于光滑