Question

2. Man's first walk on the moon was a great technological         .

   A. success   B. achievement

   C. discovery   D. invention

Answer 1

2. B achievement指"(不顾困难，通过努力所取得的) 成就"，尤指科技、学术等方面的成就； success也表达"成就，成功"之意，但指的是"获得认可，获得某地位(=to do well,especially in gaining position or popularity in life) "之意; discovery意为"发现"；invention指"发明"。