A:①③
B:②③
C:③④
D:①④
对号入座
这篇文章的脉络很清晰。( )
如图:在等腰△ABC中,∠C=90º,AC=6,D 是AC上一点,若tan∠DBA=15,则AD的长为( )
The discovery of the new drug is of great significance to people _______ from heart problems.
北京温暖干燥,多风沙的季节是( )