by preference

• 首先

by preference的用法和样例：

例句

1. The substrate is first covered by a mask.
   首先在基片上覆盖一个掩膜片。
2. He began at the beginning,by changing GE's goal.
   韦尔奇首先着手改变通用电气公司的目标。
3. You'd better send the letter by air.
   这封信你最好寄航空。
4. She is by far the best teacher I have ever had.
   她是我一生中所遇到的最好的老师。