2 sentences for 落空 (là​kòng)

1. 填表时请看清楚，不要把这一项落空了。

   tián​biǎo shí qǐng kàn qīng​chu, bù yào bǎ zhè yī xiàng là​kòng le.

   Please look carefully when filling out the form; do not leave this item blank.

   Source: Dong Chinese Dictionary

2. 打印的时候出了点差错，把其中几页的页码给落空了。

   dǎ​yìn de shí​hou chū le diǎn chā​cuò, bǎ qí​zhōng jǐ yè de yè​mǎ gěi là​kòng le.

   There was a mistake during printing, and the page numbers on a few pages were left out.

   Source: Dong Chinese Dictionary