подобрать однокоренные существительные во множественном числе к глаголам - косить, уколоть, посадить, гостить, возить.

Тело движется прямолинейно по закону [tex]S(t)= -\frac{1}{3}^{3}+t^{2}+15t+8[/tex]

Найти скорость тела через 4 секунды после начала движения.

Помогите решить пожалуйста

Поставьте данные в скобках глаголы в форму либо простого прошедшего,либо настоящего совершенного времени(Past Simple,Present Perfect) 1 I just(tell)you the answer. 2 I(tell)you the answer yesterday. 3John and Richard just(go)away. 4She already(answer)the letter. 5She(answer)the letter on Tuesday. 6John and David(go)away fine minutes ago. 7 I(read)that book in June. 8 I(not, see)him for three years. I want to know where he is. 9 I(fly)over Loch Ness last week. — You (see)the Loch Ness monster? 10 When he (come)?- He (come)at 2,00. 11 I (read)his books when I was at school. I (like)them very much. 12 I can't go out because I (not,do) my work. 13 I (write) the letter but I can't find a stamp. 14 I (leave)home at 8.00 and (get)here at twelve. 15 You (have)breakfast yet?-Yes, I (Have)it at 8.00. 16 I (meet)him last June. 17 You (see) the film last night? 18 The film just (begin).You are a little late. 19The newspaper (come)? — Yes, Ann is reading it. 20 He (break) his leg last year. 21 You (be)here before? — Yes, I (have)my holidays here last year. You (have)a good time? — No, it was raining all the time.