Conditionals / type 1 (only) 1) not only the cleaning process (in involve) labor costs, it may require special equipment, particularly if chemical cleaning (to involve)
2) fresh deposits (to form) only if the deposit bond resistance (to be) greater the prevailing shear forces at the solid-fluid interface
3) dissolution (to occur) only if there (to be) a change in the properties of the deposit
4) if the temperature of the heat exchanger surface on the water side (to be) at or below 0, then a layer of ice (to form) on the surface
5) if the skid (to be) on the shell side, it (to be) impossible to remove the tube bundle
6) if the total thermal resistance (to increase) the amount of heat transferred throughout the surface (to decrease)
7) if the layer of insulating material (to have) a high thermal resistance, higher than any other part of the heat exchangers, the total thermal resistance ( to increase)

1) Don't come without knocking
2) Don't leave the door opening
3) Don't shut the windows
4) Don't touch my notebook
5) Don't remove my things
6) Don't lie on my bed
7) Don't switch on my player
8) Don't switch off my TV
9) Don't take my books and copybooks
10) Don't enter my room if I am out
11)Don't throw the clothes
12)Don't eat in my room
13)Don't draw on the walls
14)Don't In my room should not spill water.
15)Don't screaming in the room.
16)Don't to listen to music very loudly.

1) Не входите без стука
2) Не оставляйте дверь открытой
3) Не закрывайте окна
4) Не трогайте мой ноутбук
5) Не передвигайте мои вещи
6) Не лежите на моей постели
7) Не включайте мой плеер
8) Не выключайте мой телевизор
9) Не берите мои книги и тетради
10) Не входите в мою комнату, если меня нет дома
11)не разбрасывать одежду
12)Не кушать в своей комнате
13)Не рисовать на стенах
13)Не клеить плакаты на стене
14)В моей комнате не должна пролиться вода.
15)Не кричать в комнате
16)Не слушать музыку очень громко.

who,  that ,  what,   preposition + which
1) Thank you for your e-mail in which you enquired about our products.
2) Your statement of account that we received last week, appears to have a number of errors that refer to items we did not order.
3) I would like to speak to Mr.Baker, who phoned me this week, concerning our account, that he says has not been cleared.
4) Would you please clear your balance that has been outstanding since last January.
5) To my mind, you need to contact the person who deals with foreign transactions.
6) An agent who sells products on his own account can set his own prices and profit margins.
7) Thank you for your letter of 12 April 2006 in which you asked us to give your company a ten per cent discount on your order.
8) Insurance underwriters offer two types of policy that would be suitable for your requirements.
9) With regard to the changes of our terms of payment that you asked for we suggest you should use Banker's Drafts.
10) We would like to remind you still owe our bank 2000$ that we want you to pay before the end of April