LOOK 为什么加ING

look+ing怎么加? I’m looking to this summer.look为什么加ing I look forward to seeing you.为什么see加ing look,the door is open,为什么open不加ing? looking after a children为什么look要加ing? 为什么加ing  为什么要加ing prevent为什么加ing? look forward to 后加V.ing? Look后面要加ing吗? we are all looking forward to a great day out的look为什么加ing Im lookng forward to your arrival, look为什么要加ing