现有pH=a和pH=b的两种NaOH溶液,已知b=a+2,将两种溶液等体积混和后,所得溶液的pH接近于( )
A.a-lg2
B.b-lg2
C.a+lg2
D.b+lg2
答案:B
I see a girl ____ in the garden. [ ]
A. read
B. reads
C. to read
D. reading
股静脉穿刺的注意事项有哪些?