I am a bit doubtful as always, especially of the first one! Some of them however are very easy I know!
I. 1. Helvetii cum patrum nostrorum tempore domo profecti essent, consulis exercitum in fugam dederant.
-The Helvetii, since they had set out from home at the time of our fathers, they had put the consul's army to flight.
2. Cum Caesar in Galliam venit, Helvetii alios agros petebant.
-When Caesar came into Gaul, the Helvetii began to storm other fields.
3. Caesar cum in Galliá esset, tamen de Helvetiorum consiliís certior fiebat.
-Although Caesar was in Gaul, yet he was being informed about the plans of the Helvetii.
4. Cum Helvetii bello clarissimi essent, Caesar iter per provinciam dare recusavit.
-Since the Helvetii were famous in war, Caesar refused to let them pass through the province.
5. Legatus cum haec audivisset, Caesarem certiorem fecit.
-When the ambassador had heard these words, he informed Caesar.
6. Cum principes obsides inter se darent, Romani bellum paraverunt.
-Since the chiefs were giving hostages to eachother, the Romans prepared for war.
7. Caesar, sum id nuntiatum esset, maturat ab urbe proficisci.
-Caesar, when this had been announced, hastened to set out from the city.
8. Ne virtute quidem Galli erant pares Germanis.
-Not even in virtue were the Gauls equal to the Germans.
9. Caesar neque corpore neque animo infirmus erat.
-Caesar was not infirm in body or in spirit.
10. Illud bellum tum incepit, cum Caesar fuit consul.
-That war began at the time when Caesar was consul.
II. 1. That battle was fought at the time when I was at Rome.
-Pugnatum est tum cum eram Romae.
2. Though the horsemen were few in number, nevertheless they did not retreat.
-Cum equites numero pauci essent, tamen terga non verterunt. (pedem non retulerunt)
3. When the camp had been sufficiently fortified, the enemy returned home.
-Cum castra satis munita esset, hostes domum reverterunt.
4. Since the tribes are giving hostages to eachother, we shall inform Caesar.
-Cum barbari obsides inter se dent, Caesarem certiorem faciemus.
5. The Gauls and the Germans are very unlike in language and laws.
Galli et Germani sunt dissimillimi linguá legibusque.
iús, iúris - law, right, justice, law court. Broth, soup (n)
léx, légis - law (f)
perítus - skilled, experienced