洋地黄中毒引起室性期前收缩二联律的首选治疗药物是（）

[单选题]The number of speakers of English in Shakespeare’s time is estimated (估计) to have been about five million. Today it is estimated that some 260 million people speak it as a native language, mainly in the United States, Canada, Great Britain, Ireland, South Africa, Australia and New Zealand. In addition to the standard varieties of English found in these areas, there are a great many regional and social varieties of the language as well as various levels of usage that are employed both in its spoken and written forms. In fact, it is impossible to estimate the number of people in the world who have acquired an adequate (足够的) working knowledge of English in addition to their own languages. The purpose for English learning and the situations in which such learning takes place are so varied that it is difficult to explain and still more difficult to judge what forms an adequate working knowledge for each situation. The main reason for the widespread demand for English is its present-day importance as a world language. Besides serving the indefinite needs of its native speakers, English is a language in which some of important works in science, technology, and other fields are being produced, and not always by native speakers. It is widely used for such purposes as meteorological and airport communications, international conferences, and the spread of information over the radio and television networks of many nations. It is a language of wider communication for a number of developing countries, especially former British colonies. Many of these countries have multilingual populations and need a language for internal communication in such matters as government, commerce, industry, law and education as well as for international communication and for entrance to the scientific and technological developments in the West.What forms an adequate working knowledge of English

[单选题]下列预防措施属于被动免疫的是（）

[多选题]调整分动外锁闭提速道岔的密贴时，不正确的是（）。

[问答题]设　　（1）将f（x）展开成傅里叶级数；　　（2）求该傅里叶级数的和函数S（x）及S（6）；　　（3）求的和。

[单选题]分数、、、、中最大的一个是（　　）。

[单选题]“三懂”即：懂本岗位的火灾危险性、懂（）、懂灭火方法。

[问答题]汽环有何作用？试述汽环的密封原理？

[单选题]（）是记录直接投资、证券投资、短期投资的流进和流出。

[单选题]首选的治疗是（　　）。

[单选题]（　）是借款人以合法有效、符合银行规定条件的质物出质，向银行申请取得一定金额的人民币贷款，并按期归还贷款本息的个人贷款业务。