TOEIC、TOEFL対策テスト ： Vol.29
次の記事を読んで、質問に答えてください ：
HONG KONG (Bloomberg) - China's foreign exchange reserves, the world's largest, surged to $1.68 trillion at the end of March, adding pressure on the government to prevent money inflows from fueling inflation already at an 11-year high.
Currency holdings, excluding gold, expanded 40 percent from a year earlier, the People's Bank of China said Friday on its Web site. The assets grew a record $153.9 billion from the end of December, after a $94.6 billion increase in the fourth quarter.
Exports, foreign investment and U.S. dollar depreciation have boosted China's currency assets,
hampering government efforts to rein in money supply and inflation.
（ソース：雑誌 The Daily Yomiuri : Saturday, April 12, 2008）
1. In this article, there is a synonym of the word "surge". What is it?
2. The word "hamper" is closest in meaning to
a. stop b. spoil c. impede
3. The word "rein" is closest in meaning to
a. succeed b. control c. increase
4. According to the article, what have contributed to the surge of China's foreign exchange reserves?