compound twin

例句：

1. 1. The couple is expecting their first compound twins.
   这对夫妇正在期待他们的第一对复合双胞胎。
2. 2. They are studying the genetics of compound twins to understand their unique challenges.
   他们正在研究复合双胞胎的遗传学，以了解他们独特的挑战。
3. 3. The research on compound twins has led to breakthroughs in medical treatments for these rare birth defects.
   关于复合双胞胎的研究已经导致了对这些罕见出生缺陷的医学治疗的突破。