Whydon’tyoucalldirectoryenquiriesandaskthem?It

問題詳情：

Why don’t you call directory enquiries and ask them? It ________ a new number if it’s not in the book.

A. can be               B. could be                   C. must have been              D. must be

【回答】

知識點：虛擬語氣與情態動詞

題型：選擇題