Don’t use water to put out the fire if oil catches fire. As is known, oil ____ float on water.

 --- What’s the weather like? --- Pretty hot and wet in the summer, but it _____ be quite cold in the winter. 

The problem is too difficult for him. He _______ solve it by himself without any help.

 ---Look! The light is still on. Is Mr Wu working in his office？---No, it _____ be Mr Wu. He has gone to Nanjing for a meeting. 

—Must I go there right now?—No，you ________.You ________ go there before supper.