There is a pumping lemma for CFLs similar to the one for regular sets. It can be used in the same way to show that certain sets are not context-free.

I nudged the door open further with my foot and called out: Candygram. Candygram for Mr. Nagel.

Professor Cusins: you are a young man after my own heart.

The bottom of the barrel was scraped on August 22 when Shrewsbury had to produce Taunton 2-6-0 No. 6312 to work the 8.10 p.m. from Paddington between Wolverhampton and Shrewsbury; the stranger was in trouble in the early hours of the next morning at Hollinswood, but managed to reach Shrewsbury.