Left: relation between stellar mass and SFR for ADF22.A2, ALESS SMGs at z >  3.5 (da Cunha et al. 2015), and H-dropout galaxies (Wang et al. 2019). Cyan lines show the main-sequence of z ∼ 4 galaxies (Schreiber et al. 2017). ADF22.A2 is located at a region that is overlapped by the ALESS SMGs and H-dropout galaxies. (right) [C I](1–0)/CO(4–3) Line luminosity ratio as a function of [C I](1–0) line and IR luminosity ratio for ADF22.A2 and SMGs at z ∼ 3 (Alaghband-Zadeh et al. 2013; Cañameras et al. 2018; Nesvadba et al. 2019) and SMGs at z ∼ 4 (Bothwell et al. 2017). ADF22.A2 is located at the same region where the SMGs distribute in the diagram.