Select all that apply: which sentences correctly express the same current obligation at the ceramics studio?
Potters had to wear eye protection while using the wheel.
Potters must wear eye protection while using the wheel.✓الإجابة الصحيحة
Potters must to wear eye protection while using the wheel.
Potters have to wear eye protection while using the wheel.✓الإجابة الصحيحة
الشرح
Both must wear and have to wear state that eye protection is required now. Must to wear breaks the bare-infinitive rule, and had to wear shifts the obligation into the past.