为提高换热器的传热速率，流体流向往往选择（）。
A.折流
B.错流
C.逆流
D.并流
参考答案：C
下列哪种病变常出现肠上皮化生?（）
A.表浅性胃炎
B.胃溃疡恶变
C.肥厚性胃炎
D.萎缩性胃炎
It was in the garden of his old house _____ he dug up a pot of gold. [ ]
A. which
B. where
C. that
D. how
