Using "it" as a subject is another problem that Vietnamese learners have to face. Impersonal "it" is very often used in English (example: It is raining, it is necessary etc). There is no equivalent of impersonal "it" in Vietnamese.
In the example above “it is raining”, Vietnamese language identifies the subject and uses the word "trời" (which means heaven) as a subject. Basically, literary translated, the sentence will be: "heaven is raining".
Another good example that reflects the usage of impersonal "it" is: "It is very easy to speak Vietnamese". This sentence, translated will look like: lit. Speak – Vietnamese – easy – very.
Verb series is another “feature” of Vietnamese language that is not found in English. Most situations require a second verb (that’s why it is called verb series) and by far the most used such verb is "cho", which means "give". This Vietnamese verb is often translated into English as "for".
A very good example will be: "I bought him a book". This simple statement, in Vietnamese looks like: lit. I – buy – give – he – one – (classifier) – book. In order to express the exact time, Vietnamese uses additional words such as: yesterday, just, two minutes ago etc. When such words are used the listener understands the time when action happened. This is one of the most important reasons of misuse of Past Tense in English by Vietnamese learners of English.