【单选题】I found ___________ hard to remember all the twelve star signs because they are difficult to pronounce(发音) and spell.
【单选题】有关影响沉淀完全的因素叙述正确的是 ( ) 。
【单选题】计算机操作系统在安装完毕后,为保证系统不受病毒破坏,下面的操作最可靠的是()
【单选题】Many road signs can be found all over the world.
【单选题】Not all road signs in this world are funny.
【多选题】有关影响沉淀完全的因素叙述正确的是 ( )
【单选题】I ___ (对......感动困惑)the road signs.