用所给动词的适当形式填空。 1. I'm calling to tell you that I ___________ (not be) able to go to the gym with you tonight. 2. The teacher told us that light ___________ (travel) much faster than sound. 3. I ___________ (think) they were having a meeting at that time. 4. I will go with you if she ___________ (go). 5. If it ___________ (rain) tomorrow, I won't go to the museum.