5. The ice on the lake was so thin that
people couldn’t skate on it.
The ice on the lake was not _________
enough _________people _________ _________ _________ it.
[答案]thick;
for; to skate on。形容词或副词+enough
+to do sth,意为“足够……以致于能够……”,用来替换“so…that+结果状语从句”。