Question: Not Alone, is Zhang Liyin's which number overall single, Zhang held a showcase to support the release of the single, which was held at the Century Theater in Beijing, EXO members Tao and Chen were guests, Exois a South Korean-Chinese boy group based in Seoul? 
Sentence (from "Zhang Liyin"): She speaks both Mandarin, which is her first language, and fluent Korean, and has released singles in both China and South Korea, singing in both languages.
Relevant evidence: No