标题: OG-12 # 14关于conjuction but 前是否一定要用"," [打印本页] 作者: smileGMAT1 时间: 2012-2-21 00:25 标题: OG-12 # 14关于conjuction but 前是否一定要用"," 14. Sunspots, vortices of gas associated with strong electromagnetic activity, are visible as dark spots on the surface of the Sun but have never been sighted on the Sun's poles or equator.
坐等nn解答！作者: smileGMAT1 时间: 2012-2-21 03:19 作者: h14zpsn 时间: 2012-2-21 03:38
不用的，主要还是得看逻辑的情况，比如这题就在but前面不用comma eg. Ozone is a harmful pollutant but shields the Earth from the most biologically harmful radiation emitted by the Sun, radiation in the ultraviolet band of the spectrum.作者: smileGMAT1 时间: 2012-2-21 08:19
不用的，主要还是得看逻辑的情况，比如这题就在but前面不用comma eg. Ozone is a harmful pollutant but shields the Earth from the most biologically harmful radiation emitted by the Sun, radiation in the ultraviolet band of the spectrum.
,外加我用的是手打的电子版，不太确定是否为打印错误。