以下哪个可能是红外发射管? <img src="http://static.cnmooc.org/repositry/umeditor/i/1809/21/3ae9e2e59549454a9b070ff118168864.jpg" />|<img src="http://static.cnmooc.org/repositry/umeditor/i/1809/21/394f173e66bd4376b5fcef9c399105b6.jpg" />|<img src="http://static.cnmooc.org/repositry/umeditor/i/1809/21/502a44e8f77f40078a8d9519a1e6923a.jpg" />|<img src="http://static.cnmooc.org/repositry/umeditor/i/1809/21/dd21e7635f994ad1a0134d620715fb1f.jpg" />

<img src="http://static.cnmooc.org/repositry/umeditor/i/1411/4/a0381dde30eb4b27b866a70b1f295122.png" />? <img src="http://static.cnmooc.org/repositry/umeditor/i/1411/4/fbf79006ab1245ca8e0ba53872aaf260.png" />|<img src="http://static.cnmooc.org/repositry/umeditor/i/1411/4/42540ee32abb4be996cd99da70528049.png" />|<img src="http://static.cnmooc.org/repositry/umeditor/i/1411/4/93d9567d6cb041de9ebd7a540c45c701.png" />|当L值越小时，到达极值点指定邻域所需要的步数越多

按钮在会声会影中的作用（ ）http://210.41.168.88/repositry/umeditor/i/1610/28/f9750bb57063437ab00ce1004b52c57c.png

文件利用Cool edit软件打开时，文件类型需要修改为（ ）。http://210.41.168.88/repositry/umeditor/i/1610/13/4789eca80b9b4a75a7bae146dce443af.png/js/editor20150812/themes/default/images/spacer.gif