I think it is really advisable for all of us to participate in the activity.此句话中is是否可不要
问题描述：
I think it is really advisable for all of us to participate in the activity.此句话中is是否可不要
答
可以不要,但句子结构大不同
I think it is really advisable for all of us to participate in the activity
it is really advisable for all of us to participate in the activity作为宾语从句,前面省略了that
I think it really advisable for all of us to participate in the activity
really advisable for all of us to participate in the activity作为it的宾语补足语