题目选项分析

The yield of natural gas from Norway's Troll gas field is expected to increase annually until the year 2005 and then to stabilize at six billion cubic feet a day, an extraction rate that will allow at least 50 years' production.

The yield of natural gas from Norway's Troll gas field is expected to increase annually until the year 2005 and then stabilizing at six billion cubic feet a day, with such an extraction rate at the least allowing 50 years' production.