关于化疗下列错误的是( )

A．合理使用静脉，并注意保护原则

B．在穿刺成功后，先注入生理盐水观察有无外渗，再加入药物

C．药物注射终了后，再注射入等渗盐水后方可拔针

D．药物注射终了即可拔针

E．拔针后应轻压静脉穿刺点数分钟，防药物外渗

---It’s a long time _____ I saw you last.

---Yes, and what a pity it is now that it will be a long time _______ we see each other again.

A．before; since

B．since; when

C．since; before

D．when; before