The development of Bas 90 began in the 1970s and started implementation in the 1980s .
The development of Bas 90 started in the 1970s and was implemented in the 1980s .
The development of Bas 90 started in the 1970s and was implemented in the 1980s .
解释一下这段文字: The development of Bas 90 began in the 1970s and started implementation in the 1980s . 输出: