visit的名词形式可数吗?
问题描述：
visit的名词形式可数吗?
或者直接告诉我这题选什么?
I haven't seen Mr.black and his wife for a long time.
------Blacks are on -------visit to Africa.
A./;a B.A;the CThe;a DThe;/
答
选C-
The-----Blacks are on a-visit to Africa.