Studying high-mass star formation from observations

High-mass stars play a major role in Galaxy formation and evolution. However, their formation is still far from well known due to their large distances.  Two models for high-mass star formation are very popular in recent years, "core accretion model" and "competitive accretion model". I will talk about how to distinguish these two models from observations. Especially, I will talk about our efforts on high-mass star formation studies in the ALMA era.