拔牙后3-5天出现出血是因为()

A．牙槽窝内断根未取出

B．牙槽骨骨折

C．牙龈撕裂

D．创口感染

E．干槽症

选出与所给句子划线部分意义相同或相近的一项。

—Terrible earthquakes happened in some parts of the world this year.

—I'm sorry to hear that. [ ]

A. took place

B. took the place

C. broke down

D. put down