the authorities: the group of people with official power in an area, like the government
blew up: destroyed with a bomb or explosives
security concerns: worries about safety and the threat of terrorism
the backbone of: the most important part of something which holds the rest together
ski slopes: areas on the sides of mountains, hills and artificial hills used for the sport of skiing

Use one of the words or phrases below to complete each of these sentences from a BBC news report.

Note that you may have to change the form of a word to complete the sentence correctly.
the authorities / blew up / security concerns / the backbone of / ski slopes

1.
And, in another mysterious and high-profile case in 2003, US pizza delivery man Brian Wells was killed when a collar bomb he was wearing __________ after he robbed a bank in Pennsylvania.

2.
Saif al-Islam, one of the Libyan leader's sons, sought to rally regime forces earlier on Tuesday by making a defiant appearance and claiming the regime had broken ___________ the rebel advance.

3.
His beating-up by security forces shows that he has hit home and that __________ tolerance for dissent is touching zero.

4.
Glasgow Caledonian University's Moffat Centre, which monitors visitor attractions, said Scotland's __________ benefited most from heavy snowfalls.

5.
Brazil had been scheduled to play African champions Egypt on Tuesday 6 September, but the game was cancelled due to __________ in Cairo.