Backstroke

No matter how hard I practiced, I wasn't able to do the backstroke.

"Waitress, what's this fly doing in my soup?" "Looks to me to be backstroke, sir!"

I can do breaststroke but not backstroke.

I can do the breaststroke but not the backstroke.

I've finally learnt the backstroke!

I can do the breaststroke, but not the backstroke.

He observed that Cid Ruy-dias was an excellent knight; but not equal to the Lord of the Flaming-sword, who with one back-stroke [translating revés] had cut two fierce and monstrous giants through the middle.