Attempts have been made for nearly three decades to increase the amount of precipitation from clouds by seeding them with salt or silver iodide.

A．Devices

B．Hypotheses

C．Efforts

D．Suggestions

吸入麻醉药对乙酰胆碱作用主要是()

A．抑制其摄取

B．使其降解

C．抑制其活性

D．减少其释放

E．加速其摄取