Journals

Progress in Polymer Science

Chemical Industry and Engineering Progress

Tense

Past

Present

Present perfect

Past

Present

Present perfect

actual frequency f_o

M1

0

43

5

0

37

16

M2

0

46

2

16

26

11

M3

0

42

6

22

31

0

M4

0

48

0

24

29

0

expected frequency f_e

16.83

16.83

16.83

16.83

16.83

16.83