单选题 You can’t enter the lab ____ you have a special pass.

单选题 This course is designed to focus ____ practical communication skills.

单选题 The fact ____ he resigned surprised everyone in the company.

单选题 Only then ____ realize how important health is.

单选题 It usually ____ about two hours to fly from here to Beijing.

单选题 ____ difficult the task is, we will try our best to complete it.

单选题 If I ____ more time yesterday, I would have finished the report.

单选题 If I ____ you, I would think twice before making the decision.

单选题 ____ he is very busy, he still spares time to read every day