【单选题】The percentage of purchases on credit cards this year drops by______since 2007.
【单选题】Other commitments remain sparse despite the plan______since 2007.
【单选题】“Rubber Duck”,________ by Dutch artist Florentijn Hofman,has visited many cities since 2007.
【单选题】锆盐-枸橼酸反应生成的黄色物加枸橼酸后不褪色的是( )
【单选题】-_____have you been in Beijing? -Since 2007.
【单选题】They studied what ______ since 2007 and found Australian electricity prices were among the highest in the developed world.
【单选题】Tick bites(蜱虫叮咬)are reported _______ in 12 provinces and claimed 31 lives since 2007.
D.
to have been broken out
【单选题】The word 'foolish' is too mild to describe your behavior, I would prefer the word ______.
【单选题】The world has been shaken by a huge financial crisis since 2007; thanks to each country’s powerful policies, the international trade is improving _________ day by day.
【简答题】焊前准备的几点要素,如装配间隙、钝边大小、反变形大小的确定。