______is very important for us students to learn English well.
---Your job _______ open for your return. --- Thanks.
Who will _______ the company if our manager isn’t here next week?
Jack has three sons, and both of _______ are studying in China.
--- What is the price of petrol these days?--- Oh, it _______ sharply since last month.
The old lady was so pleased with all _______ we had done for her _______ she wrote us a thank-you letter.