1. patients with severe or critical covid-19 who currently require hospitalization, or patients who are expected to develop into severe or critical disease and require hospitalization within 48h after randomization. 2. difficulty swallowing or a history of gastrointestinal diseases that seriously affect drug absorption. 3. active liver disease, or obvious abnormal liver function (alt or ast ≥ 3uln, or total bilirubin ≥ 2uln). 4. wbc \>1uln, or neu \<0.5ⅹ109/l. 5. receiving dialysis or have known moderate to severe renal impairment (egfr\<60ml/min/1.73m2). 6. other suspected or confirmed systemic infections. 7. current or expected use of strong cyp3a4 inducers, inhibitors or medications that are highly dependent on cyp3a4 or cyp2c19 for clearance. 8. prior or anticipated receipt of any vaccine within 28 days prior to enrollment and during study period. 9. use of antivirals against sars-cov-2 within 7 days prior to enrollment. 10. weight≤40kg. 11. pregnant, lactating women or those with a positive pregnancy test (sterilized or postmenopausal women may not have a pregnancy test). 12. previous administration with any investigational drug within 3 months before the study drug administration. 13. participants who are judged by the investigator to be unsuitable to participate in this study.

1. patients with severe or critical covid-19 who currently require hospitalization, or patients who are expected to develop into severe or critical disease and require hospitalization within 48h after randomization. 2. difficulty swallowing or a history of gastrointestinal diseases that seriously affect drug absorption. 3. active liver disease, or obvious abnormal liver function (alt or ast ≥ 3uln, or total bilirubin ≥ 2uln). 4. wbc \>1uln, or neu \<0.5ⅹ109/l. 5. receiving dialysis or have known moderate to severe renal impairment (egfr\<60ml/min/1.73m2). 6. other suspected or confirmed systemic infections. 7. current or expected use of strong cyp3a4 inducers, inhibitors or medications that are highly dependent on cyp3a4 or cyp2c19 for clearance. 8. prior or anticipated receipt of any vaccine within 28 days prior to enrollment and during study period. 9. use of antivirals against sars-cov-2 within 7 days prior to enrollment. 10. weight≤40kg. 11. pregnant, lactating women or those with a positive pregnancy test (sterilized or postmenopausal women may not have a pregnancy test). 12. previous administration with any investigational drug within 3 months before the study drug administration. 13. participants who are judged by the investigator to be unsuitable to participate in this study.

patients with severe or critical covid-19 who currently require hospitalization, or patients who are expected to develop into severe or critical disease and require hospitalization within 48h after randomization. difficulty swallowing or a history of gastrointestinal diseases that seriously affect drug absorption. active liver disease, or obvious abnormal liver function (alt or ast ≥ 3uln, or total bilirubin ≥ 2uln). wbc >1uln, or neu <0.5ⅹ109/l. receiving dialysis or have known moderate to severe renal impairment (egfr<60ml/min/1.73m2). other suspected or confirmed systemic infections. current or expected use of strong cyp3a4 inducers, inhibitors or medications that are highly dependent on cyp3a4 or cyp2c19 for clearance. prior or anticipated receipt of any vaccine within 28 days prior to enrollment and during study period. use of antivirals against sars-cov-2 within 7 days prior to enrollment. weight≤40kg. pregnant, lactating women or those with a positive pregnancy test (sterilized or postmenopausal women may not have a pregnancy test). previous administration with any investigational drug within 3 months before the study drug administration. participants who are judged by the investigator to be unsuitable to participate in this study.

patients with severe or critical covid-19 who currently require hospitalization, or patients who are expected to develop into severe or critical disease and require hospitalization within 48h after randomization. difficulty swallowing or a history of gastrointestinal diseases that seriously affect drug absorption. active liver disease, or obvious abnormal liver function (alt or ast ≥ 3uln, or total bilirubin ≥ 2uln). wbc >1uln, or neu <0.5ⅹ109/l. receiving dialysis or have known moderate to severe renal impairment (egfr<60ml/min/1.73m2). other suspected or confirmed systemic infections. current or expected use of strong cyp3a4 inducers, inhibitors or medications that are highly dependent on cyp3a4 or cyp2c19 for clearance. prior or anticipated receipt of any vaccine within 28 days prior to enrollment and during study period. use of antivirals against sars-cov-2 within 7 days prior to enrollment. weight≤40kg. pregnant, lactating women or those with a positive pregnancy test (sterilized or postmenopausal women may not have a pregnancy test). previous administration with any investigational drug within 3 months before the study drug administration. participants who are judged by the investigator to be unsuitable to participate in this study.