26．The traffic in Beijing will be better when Subway Line 16 ______ into service.
A
would be put
B
was put
C
will be put
D
is put
在时间状语从句中，主句用将来时，从句用一般现在时，故选D。
考查动词的时态。
没有注意到时间状语从句中特殊的时态而误选C。