I spent half an hour ___________ my homework.
— I always feel a little nervous when I talk to the headmaster.— ______ . She is strict, but she’s also kind to her students.
______ may have a chance to be successful if he tries his best.
You will fall behind the others ______ you start to work hard.
— Excuse me. Is the museum open all day long?— ______ , only from 9:00am to 5:00pm.
The student ______ his homework and handed it to the teacher.