--- I really enjoyed talking with you ---but I’m afraid I must be off now!

---_____.

A．My pleasure

B．Nice to see you

C．Sorry to trouble you

D．So long

有关下列地区发生泥石流成因类型差异的正确叙述是

A．青藏高原东南部山地属于暴雨引发的泥石流

B．天山山地属于降水引发的泥石流

C．黄土高原属于暴雨激发的黄土泥石流

D．华北和东北山区属于冰川引发的泥石流