Do you know the reason _______ he was late?

His pale face suggested he ________ angry and I suggested that he ________ at once.

He’s got himself into a dangerous situation ____ he is likely to lose control over the plane.

Ms. Claire is a strict but kind teacher, _____ who, usually, _____ her students.

Beijing government puts more than 700 million yuan to increase its green space this year,____________ doubles the money provided last year.