In your portfolio, you get to choose which grammatical items you feel you want to improve most. Is it verb tenses? Is it sentence building? Is it the difference between much and many? Or did you come across a Wasp Reporter exercise that got your interested?
On this website you will find a grand list of all possible grammatical topics. This website has a handy dandy reference chart of grammatical items and the corresponding level. 4H should be working towards level B1 or B1+.