instruction:
In this task, we ask you to elaborate the sentence without changing its general meaning. You can do so by explaining further the input sentence, using more precise wording, adding qualifiers and auxiliary information etc.
question:
SEHK , is a stock exchange located in Hong Kong .
answer:
The Stock Exchange of Hong Kong ( SEHK , also known as Hong Kong Stock Exchange ) is a stock exchange based in Hong Kong .


question:
A head teacher ( also called a school principal , or headmaster / headmistress ) is the teacher in charge of a school .
answer:
A head teacher , headmaster , headmistress , head , chancellor , principal or school director ( sometimes another title is used ) is the staff member of a school with the greatest responsibility for the management of the school .


question:
Several double-blind experiments suggest that people who say they have EHS ca n't detect if electromagnetic fields are present , and are just as likely to report feeling sick after a phony exposure as they are after real exposure , making scientists think it is the nocebo effect .
answer:

Since then , several double-blind experiments have shown that people who report electromagnetic hypersensitivity are unable to detect the presence of electromagnetic fields and are as likely to report ill health following a sham exposure as they are following exposure to genuine electromagnetic fields , suggesting the cause in these cases to be the nocebo effect .