Choose 'no', 'few' and 'little' instead of 'none', 'not many' and 'not much'
How to choose between formal and less formal negative expressions.
In the formal register, you should express the negative with one word, such as no, few, and little. It is also recommended that you put the negation in the longer word, such as insufficient instead of not sufficient in example 4b. This also reduces the need for contractions, which should be avoided :
Less formal:
(1a) This problem doesn’t have an environmentally friendly solution.
More formal:
(1b) This problem has no environmentally friendly solution.
Less formal:
(2a) There aren’t many relevant models of cardiovascular disease in these species.
More formal:
(2b) There are few relevant models of cardiovascular disease in these species.
Less formal:
(3a) There hasn’t been much development in this area.
More formal:
(3b) There has been little development in this area.
Less formal:
(4a) Participants didn’t allocate sufficient time to the final question.
More formal:
(4b) Participants allocated insufficient time to the final question.