The error I see most often with transitions is that “moreover” is used too often. In English written by native speakers, “moreover” is not used very often. When it is used, it indicates that the statement it introduces adds a stronger argument to the preceding statement. Here is an example of how “moreover” should be used:
The number of graduates is increasing and the number of academic positions is decreasing. Moreover, funding is becoming scarcer, so even when graduates are able to find academic positions, they struggle to fund their research.
In the example, you can see the second statement strengthens the argument significantly; it provides more than just additional information or another example.
Another transition that is used too often in NNSE writing is “furthermore”. This is another word that is only occasionally used by native speakers, and its meaning is very similar to “moreover”. It does not imply that the statement it introduces is a stronger argument, though; only that it is an additional argument to consider.
There are many good alternatives for “moreover” and “furthermore”, such as “in addition”, “additionally”, “also”, “as well”, “further”, “too”, “what’s more”, and sometimes just “and”. They should not all be used the same way in a sentence, though; “in addition”, “additionally”, “further”, and “what’s more” should usually be used to start a sentence or statement, but the others should not. The transitions “as well” and “too”, in fact, often belong at the end of a sentence or phrase.
Another common error is inappropriate use of “besides”. It is often used by ESL writers at the beginning of sentences to mean “additionally”. In formal writing, however, “besides” should not generally be used to start a sentence (“additionally” or “in addition” are better for that purpose). “Besides” indicates a supporting but secondary argument, or “apart from”. In addition, as explained above, after the “Test yourself (1)” exercise, in formal language “besides” should always be followed by an object or an action.
I also often see “in contrast” and “on the contrary” confused. While “in contrast” is used to introduce a statement that contrasts the preceding statement, “on the contrary” introduces one that contradicts the previous statement. The words “contrast” and “contradict” are somewhat similar and therefore confusing; here are their definitions:
Contrast means to differ strikingly from something else.
Contradict means to assert the opposite of a previous statement.
Thus “in contrast” has a wider definition — a contrasting statement could be a direct contradiction or just something that is different — but “on the contrary” is more precise, and should only be used to introduce a direct contradiction.
Thus, one could say:
The sisters were dressed in red. In contrast, their brother wore blue.
“On the contrary” would not make sense in this context, because the brother wearing blue does not contradict the fact that the sisters wore red.
However, “on the contrary” makes sense in this sentence:
You said it would be sunny and hot today! On the contrary, it was cold and rainy all day.
“In contrast” would make sense in this context, but it would sound a bit unnatural and stilted. “On the contrary” is more precise and natural. Here is another example:
We predicted that the new design would be more robust than the old one. On the contrary, it was not able to withstand dropping from the same height, and was not at all waterproof.