3 sentences

1. 他的考试成绩平平，并不出众。

   tā de kǎo​shì chéng​jì píng​píng, bìng bù chū​zhòng.

   His exam results were mediocre and not outstanding.

   Source: Dong Chinese Dictionary

2. 他才华平平，却总是自命不凡，看不起别人。

   tā cái​huá píng​píng, què zǒng​shì zì​mìng​bù​fán, kàn​bu​qǐ bié​ren.

   He has mediocre talent but is always pretentious and looks down on others.

   Source: Dong Chinese Dictionary

3. 由于缺乏明星的拉力，这部电影的票房表现平平。

   yóu​yú quē​fá míng​xīng de lā​lì, zhè bù diàn​yǐng de piào​fáng biǎo​xiàn píng​píng.

   Lacking star power, the film's box office performance was mediocre.

   Source: Dong Chinese Dictionary