ZAO Learnfast is a publisher of study materials for professional students. It entered into contracts with Anna and Yevgeni under which they would produce study texts, with each text to be divided into 12 chapters of approximately equal length.Shortly after beginning to write her study text, Anna discovered that the work was too demanding. She wrote to ZAO Learnfast explaining this, enclosing drafts of the three chapters she had managed to complete, together with her invoice for one-quarter of the fee.Three months after entering into the contract with Yevgeni, ZAO Learnfast was advised by the relevant professional body that the subject on which Yevgeni was writing his study text would be withdrawn within a year. ZAO Learnfast wrote to Yevgeni explaining that his study text would no longer be required. By this time, Yevgeni had written three chapters of the study text. ZAO Learnfast is prepared to pay Yevgeni one-quarter of the fee specified in the contract.The contracts between ZAO Learnfast and the two writers made no provision for these events.Required:

(a) Discuss the consequences of Anna’s withdrawal from her contract with ZAO Learnfast. (5 marks)

治疗短暂性脑缺血发作气虚血瘀脉络瘀阻证，应首选( )

A．镇肝熄风汤
B．补阳还五汤
C．黄连温胆汤合桃红四物汤
D．羚角钩藤汤
E．半夏白术天麻汤