Parallelism - balancing a sentence

A balanced sentence construction, also known as a parallel structure, is essential for syntactically sound writing. It means that the first structural choice you make in a sentence must be maintained as the sentence continues. 

Rather than spending time on explanation, let us look at many examples.

The following sentences fail the parallelism test [the correct form is shown in the brackets after each one]. 

Whisky  must be made from at least 51% corn; it must be aged in charred new oak barrels; only pure water can be added to it; and it must not exceed 125 proof going into the barrel [it can be diluted with pure water only].

The class has one French student, several Italians, Peter who is from England, and Anastasia who is a Russian [...several Italians, an Englishman called Peter, and a Russian called Anastasia].

The students who listen to me, laugh at all my jokes and if they are prepared to follow my instructions will get top marks [...who listen to me, laugh at all my jokes, and are prepared to follow my instructions will get top marks].

John's pronunciation of English is the same as Peter, who is from the same country [...the same as Peter’s...].

The best things to do when learning vocabulary is to choose a few words only, turn off the radio, music, the internet, walk about the room and visualizing the word [...and visualize the word].

The courses are taught by teachers, but the schedules for the classes by the University Administration [...but the schedules for the classes are set by the University Administration].

Eating all the food was selfish enough of you, but to allow my cat to starve too was cruel [...but allowing my cat to starve too was cruel].

It is neither nice or polite to point out grammar mistakes, but alas it is my job [It is neither nice nor polite…].  

I have some books here both for Paul and Maria [I have some books here both for Paul and for Maria OR I have some books here for both Paul and Maria].

I tell people I come either from Ireland or England or, sometimes, America; it depends on who I am talking to and how much I want to confuse them [I tell people I come either from Ireland or from England or, sometimes, from America…].

If we continue burning fossil fuels and to increase the power of computers, the world in 2025 will have loads of iPads and no people in it [If we continue burning fossil fuels and increasing the power of computers…].

I don’t want to bother carrying a suitcase or get a taxi, so I am boarding the plane in jogging gear and will run from the airport to my hotel [I don’t want to bother carrying a suitcase or getting a taxi…].

I can easily eat my fill at the dinner and to run all the way back home [I can easily eat my fill at the dinner and run…].

I am taking plenty of food both for myself and my walking partner [I am taking plenty of food both for myself and for my walking partner OR for both myself and my walking partner].

Either you do what I say or will suffer the consequences [Either you do what I say or you will suffer the consequences].

Her tactic is always to sit in the corner and peering out from there [Her tactic is always to sit in the corner and peer out from there].

The advantages of being a teacher are seeing the light in students’ eyes when they understand something, and you can also use a big stick [The advantages of being a teacher are seeing the light in students’ eyes when they understand something, and being able to use a big stick].

If you have a large debt, you can either pay it or you can run away to another country [If you have a large debt, you can either pay it or run away to another country].

Running marathons and exercising are not as fun as cigars and whiskey [Running marathons  and exercising are not as fun as smoking cigars and drinking whiskey].

Sinead looks bored and like she would rather be anywhere but here [Sinead looks bored and looks like she would rather be anywhere but here].

I have an aptitude to risk, but never gone skydiving [I have an aptitude to risk, but I have never gone skydiving].

Federica has a bath every day, but no friends [Federica has a bath every day, but she has no friends].

It is easier to learn new things than unlearning ingrained bad habits, which is why foreign students often do well in composition [It is easier to learn new things than to unlearn ingrained bad habits…].

Getting married is easy, to stay married is hard [Getting married is easy, staying married is hard].

English grammar is far harder than appears to beginners [English grammar is far harder than it appears to beginners].