题目选项分析

The spokeswoman for the national laboratory announced that, while the lab had been operating at a loss in the 1990s, it had become profitable in 2006, and would continue to yield high profits at least until 2025.

The spokeswoman for the national laboratory announced that, while the lab had been operating at a loss in the 1990s, although becoming profitable in 2006, and will continue to yield high profits at least until 2025.