Complex Sentences in IELTS Task 1
My first language is NOT English. Currently I am preparing for IELTS exam.
Today I saw a youtube video about IELTS writing task. In this video, the teacher gave an example of complex sentence which is:---
"The amount of people from an English town deciding to start a vegetarian diet increased steadily by approximately 125 from about 75 to 200 between 2004 and 2007".
In another video, the teacher gave some more examples of complex sentences:-
--- Between 2004 and 2007, the number of people increased steadily from about 75 to 200.
--- There was a steady increase in the number of people from about 75 to 200 between 2004 and 2007.
--- The number of people becoming vegetarian experienced a steady increase from about 75 to 200 between 2004 and 2007.
I myself cannot see any subordinate clause or dependent clause in the four sentences. I do Not know why are they considered as complex sentences.
Can anyone help me asap please? My IELTS exam is very near :(.
Thanks a lot.