G. Verb showing ability or possibility such as néng(able to), huì (know how to), kěyǐ可以(may), etc., do not take verb-suffix le.

 

7.1     xiǎo de shíhou huì(x) shuō Yīngwén, kěshì xiànzài dōu yǐjīng wàng le. 

          我小的时候会说英文,可是现在都已经忘了。

When I was young, I could speak English; but I’ve already forgotten it all now.

 

7.2     Yǐqián zhèi dìfang kěyǐ(x) chōu yān, kěshì xiànzài xíng le. 

          以前这个地方可以抽烟,现在不行了。

Before smoking was allowed here, but not any more now.