青海生态文化的特点有（）。
A.适应性
B.实用性
C.淳朴性
D.原始性
参考答案：A, B, C
When he _____ the door, he found his keys were nowhere. [ ]
A. would open
B. opened
C. had opened
D. was to open
创口创缘整齐，容易损伤血管和神经（）
A.挫裂伤
B.切割伤
C.撕裂伤
D.砍伤
E.咬伤
