下列加横线成语使用不正确的一项是（ ）

Are you free after school—Sorry: I’ve planned to treat a friend ofmine to dinner for his help

, the great mother, in order to save her sick child, kept waiting for four hours in the heavy snow.

Mr Chen __________ his mobile phoneto the shop because it can’t work at all.

The president, together with his bodyguards, ____ to the nuclear station___ there was an accident20 minutes ago [ ]