慢性铜质沉着症的典型表现为（）

A.角膜前弹力层沉着

B.黄斑出血

C.虹膜变绿色

D.棕红色玻璃体泥浊

E.向日葵样白内障

Which is the proper method of determining whether a portable CO₂ fire extinguisher needs recharging?（）

A.Check the tag to see when the extinguisher was last charged

B.Release a small amount of CO₂; if the CO₂ discharges，the extinguisher is acceptable

C.Weigh the extinguisher and compare the weight against that stamped on the valve

D.Recharge the extinguisher at least once each year