Acute onset cough

Main purpose: 1. Using the average number of coughs per hour within 24 hours as an indicator, evaluate the efficacy of QR052107B tablets on D10 relative to placebo in patients with subacute cough. Secondary purpose: 1. In patients with subacute cough with an average number of coughs per hour ≥ 20 times within 24 hours of the baseline period, use the average number of coughs per hour within 24 hours as an indicator to evaluate the efficacy of QR052107B tablets on D4 and D10 relative to placebo. 2. Using the average number of coughs per hour within 24 hours as an indicator, evaluate the efficacy of QR052107B tablets on D4 relative to placebo in patients with subacute cough. 3. Using the average number of coughs per hour when awake as an indicator, evaluate the efficacy of QR052107B tablets on D4 and D10 relative to placebo in patients with subacute cough. /4. Using the cough severity VAS score as an efficacy indicator, evaluate the efficacy of QR052107B tablets on D4 and D10 relative to placebo in patients with subacute cough. 4. Using the Leicester cough score as an indicator, evaluate the efficacy of QR052107B tablets relative to placebo in patients with subacute cough at D4 and D10. 5. Using the sleep VAS score as an indicator, evaluate the efficacy of QR052107B tablets relative to placebo at D4 and D10. 6. Evaluate the safety and tolerability of QR052107B tablets in patients with subacute cough.