A. old B. older C. young D. younger
A. long B. longer C. length D. longly
A. who B. whom C. that D. which
A. 轻症者仅见于直肠、乙状结肠 B. 重症者可见于全结肠 C. 重症者回肠末段亦可受累 D. 病变深度常累及结肠全层
A. who B. which C. what D. where