C. The first in a series of verbal expressions does not take le了. The second verb takes a sentence-end le了if the action is completed. If the object of the second verb is quantified or modified, the second verb takes the verb-suffix le了.
3.1 Shàng ge xīngqī-tiān wǒ qù(x) shūdiàn mai-le yì běn Hàn-Yīng zìdiǎn.
Last Sunday, I went to the bookstore and bought a Chinese-English dictionary.
3.2 Wǒ yǐjīng dǎ(x) diànhuà gàosù(x) tā zhèi jiàn shì
I have already called him to tell him about this matter.