Dear Jinkai,
Nowadays Collect Earth supports only multiple entities with table layout and a code attribute marked as "key" inside of them (what we call an **enumerated entity**): the rows in the table will be automatically generated and there will be one row for each item in the code list associated to the enumerating code attribute.
For instance in this entity you have two attributes, harvest_year and number_of_multiple_harvest.
![alt text][1]
The harvest year is marked as a key attribute and the other one is a normal code attribute.
The harvest year is a code attribute (linked to a code list of years 2000 to 2017), 2000,2004,2008,2012 and 2016), this means that in the form it will show a line per year...
![alt text][2]
Thanks,
Open Foris Team
[1]: http://www.openforis.org/support/upfiles/chrome_2017-08-01_11-23-01.png
[2]: http://www.openforis.org/support/upfiles/chrome_2017-08-01_11-27-29.png