we'll go for a walk if is fine tomorrow,哪部分是主句,怎么看出

we can go for a walk()it is fine tomorrow.A.if B.that C.so D We'll go if it is fine tomorrow.为什么主句用将来时而宾语从句却用一般现在时? we'll go for a picnic if it ___(be)fine tomorrow We'll go for a picnic if it will be fine tomorrow We'll go for a picnic if it will be fine tomorrow.求错在哪与原因 If it is fine ,we'll go for a picnic(用虚拟语气改写） If it is _____ We'll go to in the park if it is fine tomorrow We'll go to _____ in the park if it is fine tomorrow. If it ___ fine tomorrow ,we'll go swimming.A.will be B.shall We'll start if it is fine tomorrow morning. we·ll go for a picnic ifit will be fine tomorrow 改错 if it's fine tomorrow,we'll go out..和if it were fine tomorro