下列生物碱中具有解痉镇痛、散瞳及解有机磷中毒作用的是（）

A.吗啡碱

B.小檗碱

C.秋水仙碱

D.苦参碱

E.莨菪碱

Microwave communication uses high-frequency (71) waves that travel in straightlines throughthe air. Because the waves cannot (72) with the curvature of the earth, they can be (73) only over short distance. Thus, microwave is a good (74) for sendingdata between buildings ina city or on a large college campus. For longer distances, the wavesmust be relayed by means of"dishes" or (75) . These can be installed on towers, highbuildings, and mountain tops.

A．repeaters

B．radars

C．telephones

D．antennas