be affianced to sb.

例句：

1. 1. Theywere affianced in 2005.
   他们在2005年订婚。
2. 2. She is affianced to her boyfriend.
   她与她的男朋友订婚了。
3. 3. The couple has been affianced for five years now.
   这对夫妇已经订婚五年了。