18 He'll be late for the train if he (not start) …………………………… at once. 19 If you come late , they (not let) …………………………… you in. 20 If he (go…………………………… on telling lies, nobody will believe a word he says. 21 If I lend you$10, you (repay) …………………………… me? 22 We'll have to move upstairs if the river (rise) …………………………… any higher. 23 If he (work) …………………………… hard today, can he have a holiday tomorrow? 24 Ice (turn) …………………………… to water if you heat it. 25 If the house (burn) …………………………… down , we can claim compensation. 26 If you (not like) …………………………… this one, I'll bring you another. 27 Tell him to ring me up if you (see) …………………………… him. 28 If I tell you a secret, you (promise) …………………………… not to tell it to anyone else? 29 If you (not believe) …………………………… what I say, ask your mother. 30 If he (like) …………………………… the house, will he buy it?