— I'm sure our surroundings will become better.

— It is still a problem _____ we can control the pollution. [ ]

A. that

B. whether

C. if

D. why

患者胃肠热盛，大便秘结，腹满硬痛而拒按，潮热，神昏谵语，但又兼见面色苍白，四肢厥冷，精神萎顿。其病机是（）

A.虚中央实

B.真实假虚

C.由实转虚

D.真虚假实

E.实中夹虚