A、_{<IMG src="http://admintk.100xuexi.com/UpLoadImage/2013-05-07/48920c30-61ee-4ce1-a233-792a98e3dd3e.gif" width="221" height="44">}
B、_{<IMG src="http://admintk.100xuexi.com/UpLoadImage/2013-05-07/67645869-b173-4d0f-b6cb-3aa6b4b6fddf.gif" width="221" height="44">}
C、_{<IMG src="http://admintk.100xuexi.com/UpLoadImage/2013-05-07/f09c5c4f-134b-4160-b7f0-1135209cd272.gif" width="221" height="44">}
D、_{<IMG src="http://admintk.100xuexi.com/UpLoadImage/2013-05-07/e621a155-36f5-4d6a-8134-41b14af1816b.gif" width="221" height="44">}