The housing problems we are looking forward to seeing _______ have attracted the government’s attention.

A．solving

B．solve

C．solved

D．to solve

小儿初次感染结核杆菌至产生变态反应的时间是

A．48～72/小时

B．2～3周

C．4～8周

D．10～12周

E．3～4个月