According to some signs, some experts have _______ that the global economy is beginning to recover little by little.

He will be in charge of the company, for he has rich experience in business.

Beijing has ______ many buses that there isoften a traffic jam in rush hours.

Why didn’t you answer the phone last night?—I ___ when you called. [ ]

“What’s your opinion on the matter, please?” “Oh, sorry, I _______.”