I'm working through a Russian grammar book on my own. I write out all the exercises in each chapter, then record them on a cassette tape and drill them orally until I feel comfortable manipulating the grammar just with ears and tongue (like in a conversation). Unfortunately, there is no answer key in the book and the grammatical explanations and examples don't always cover all that's asked for in the exercises. I'd like to make sure I'm not drilling too many mistakes into my head, if I can help it.
In one exercise I need to give the past and future of the given sentence. One sentence is Сегодня туман. I answered Вечра был туман and Завтра будет туман thinking that туман is the subject of the sentence. Is that right or is there no grammatical subject and I should use the neuter of the verbs? (For the future tense I guess the masculine and neuter are the same, будет.)
Another question: Here I need to answer the question, У вас скоро будет контрольная? I want to answer "no". Is it У меня буду нет? There are no negative examples in the chapter.
And then some translations I'm not sure of: Are you sick or simply tired? Вы больны, но только устали?
They have been resting a long time. Они отдыхают уже давно.
How long have you been waiting for Ivan? сколько времени ты здесь ждёшь Ивана?
Thank you for any help and corrections.
Z