Some rules are almost the same _______ in the world, but rules of etiquette can be different from place to place. [ ]

A. somewhere

B. anywhere

C. nowhere

D. everywhere

慢性泪囊炎对眼球构成潜在威胁是由于（）

A.泪道探通损伤角膜

B.沙眼

C.可继发白内障

D.分泌物有大量细菌

E.泪溢