Read the article by Lai et al. (2020)http://dx.doi.org/10.1136/bmjopen-2020-043828. The authors stated their research objectives under the Introduction section on page 2 of the article, and defined the study population under the Methods section on page 2 of the article. The authors analysed and reported the outcomes, then listed four weaknesses of their study on page 7 of the article. Comment on the relevance of the third and the fourth weaknesses as you relate to their (i) research objectives, (ii) methods and (iii) recommendation(s) for future research. [6 marks]