您要查找的是不是：
- 四X綜合征Four X syndrome
- 四four
- 心臟X綜合征cardiac syndrome X
- ATR-X綜合征ATR-X syndrome: Anew mutation in the XNP/ATRX gene near the helicase domain (Fren)
- 四個(gè)tetrad
- 脆性X綜合征致病基因fragile X mental retardation- 1
- 四年four years
- 四級four-stage
- X綜合征X syndrome
- 四國Shikoku
- 五X(qián)綜合征Five X syndrome; Penta X syndrome
- 四大the four elements [earth, water, fire, wind]
- 四部four-part
- 脆X綜合征fragile X syndrome
- 四處all over the place
- 多X綜合征poly X syndrome
- 四倍fourfold
- 四舍五入round
- 三X綜合征triple-X syndrome
- 四角foursquare
