The following collection of grammatical errors are fine examples of a number of complex and indeed very complex mistakes in English grammar. The corrections are based on Swan’s Practical English Usage (2005).
“The current sports centre is on campus grounds and introduced for the benefit of students.” = The current sports centre is on campus grounds and was introduced for the benefit of students.
(178.2) Wrong ellipsis. Only a repeated word with identical function and wordclass can be left out. In this case, the verb is is a copula; the verb was is an auxiliary.
“Sylvia spoke only English in her first years and only when she went to nursery school, she really learnt speaking Dutch.” = Sylvia spoke only English in her first years and only when she went to nursery school, did she really learn to speak Dutch.
(302) Negative inversion. After initial negative adverbial ‘only …’ the auxiliary should be placed before the subject. In case there is no auxiliary, use do.
– MISRELATED PARTICIPLE
“Being in America, a ‘pizza party’ sounded very promising to hungry and weary travellers.” = When they were in America, a ‘pizza party’ sounded very promising to hungry and weary travellers.
(411.4) Misrelated participle. The subject of the adverbial -ing participle clause should be the same as the subject of the main clause.
See other: Notes On English Grammar