It puzzles the scientists _____ some mammals produce their young _____ others lay eggs.
| A．that; while | B．what; while | C．that; as | D．what; as |
推荐试卷
It puzzles the scientists _____ some mammals produce their young _____ others lay eggs.
| A．that; while | B．what; while | C．that; as | D．what; as |
试题篮
()
粤公网安备 44130202000953号
