Writing paragraphs

Exercise 12
In the following article on Nuclear Hazards the signalling words and phrases
are missing. Replace them and check your answers.
There are three separate sources of hazard related to the use of nuclear reactions to supply
us with energy. _Firstly____, the radioactive material must travel from its place of
manufacture to the power station. Even though- Although_ the power stations themselves are solidly
built, the containers used for the transport of the material are not. Unfortunately___, there are
normally only two methods of transport available, _such as /Namely__ road or rail, and both of
these involve close contact with the general public, _since_________ the routes are bound to
pass near, or even through, heavily populated areas. _Secondly____, there is the problem of
waste. All nuclear power stations produce wastes which in most cases will remain
radioactive for thousands of years. It is impossible to de-activate these wastes, and
___thus/So_____ they must be stored in one of the ingenious but cumbersome ways that
scientists have invented. _For example_ they may be buried under the ground, dropped into
disused mineshafts, or sunk in the sea. __However,____ these methods do not solve the
problem; they merely store it, __to cause/since____ an earthquake could crack open the containers
like nuts. _Finally, / Thirdly__ there is the problem of accidental exposure due to a leak or an
explosion at the power station. As with the other two hazards, this is extremely unlikely
and _____so_____ does not provide a serious objection to the nuclear programme,
__however/but____ it can happen, as the inhabitants of Harrisburg will tell you. Separately, and
during short periods, these three types of risk are no great cause for concern. Taken
together, ___even/though_____, and especially over much longer periods, the probability of a
disaster is extremely high.