1.   A security fence, with watchtowers, protects the base against attack by ground forces.

2.   Among the causes of the fall of the Roman empire were successive attacks by barbarians.

3.   An all-out attack by a Junior on a senior at a meeting is usually costly, especially if the Junior member wins.

4.   Any attack by a foreign power will inevitably bring the people of a country together.

5.   But like the old joke, they prepare for nuclear attack by gathering the wagons into a circle.

6.   Chloroplast membranes are very susceptible to attack by oxygen radicals which are generated as a by-product of photochemistry.

7.   Commanders failed to provide for an attack by sea.

8.   Government troops repulsed an attack by rebel forces.

9.   He promised attacks by his cartel would cease if the government agreed to negotiate.