1 Introduction  
2 The Sample  
2.1 The ALMaQUEST and Supplementary Samples  
2.2 Sample Definitions  
2.3 FAST H I Observations  
3 Results and Analysis  
4 Atomic-to-Molecular Gas Conversion  
4.1 Stellar Mass Distribution and Star Formation  
4.3 Ionization States  
4.4 Metallicity  
5 Summary