1. Introduction
2. Observations and data reduction
3. Data analysis and results
3.1. Detected SO and $S O_{2}$ lines
3.2. Circumstellar medium from CO, CS, and $H C O^{+}$ lines
3.3. HL Tau disk model
4. Discussion
4.1. Inflow or outflow
4.2. Origin of the SO and $S O_{2}$ emission
4.3. Influence of the streamer on disk kinematics in HL Tau
5. Conclusions