—The research on the new bird flu virus vaccine is challenging and demanding. Who do you think can do the job?

—____ my students have a try?

A．Shall

B．Must

C．Will

D．May

按脚手架的用途不同，可分为（）

A、操作脚手架

B、防护用脚手架

C、承重、支撑脚手架

D、门式组合脚手架

E、钢管扣件式脚手架