not once did he miss a jump when she took part in a horse riding competition.意思
问题描述：
not once did he miss a jump when she took part in a horse riding competition.意思
是：不止一次，还是一次都没有错过？
答
not once 一次也不
因为这是个表示否定的词组,所以置于句首时,要倒装.
是一次都没有错过的意思.