下列我国城市群中，目前已跻身世界六大城市群的时

A．长江三角洲城市群

B．珠江三角洲城市群

C．京津唐城市群

D．辽中南城市群

The branch is often used             a pencil              the girl. [ ]

A. as; to

B. for; by

C. as; by

D. by; as