题干
What good news! Such a successful gene ______ in pigs that it enables the pigs to produce human serum albumin, a protein made by the liver. Look! Here ________.
| A．have they modified…they come. |
| B．did they modify…come they |
| C．they have modified…are coming they |
| D．they modify…they are coming |
答案(点此获取答案解析）
