If ... rings the doorbell, don't let ... in.
a. someone/them
b. someone/him
c. anyone/they
d. anyone/them

If someone rings the doorbell, don't let him in.

If ... rings the doorbell, don't let ... in.

b. someone/him

Объяснение:  предложение будет переводиться как: Если кто-то звонит в дверь, не впускай его.

Удачи вам ^_^

1.called

2.from

3.many

4. them

i will try to lead small excursion on our apartment for you. so, having entered into apartment, we appear in a spacious hall. at the left there is a case and a hanger for clothes, and on the right - a curbstone and a mirror. there and then near to one party an input in kitchen, with another - doors in a bedroom of parents and a children's room. in a children's room it is light and spacious, there is an exit on a loggia. we manage here with the brother together. in our bedroom there are two beds. the left corner occupies clothes, nearby - a case for toys and books. by the way, at us fine children's library, in it very interesting books are collected. too it is a lot of toys - my brother still small.on the right party along a wall stand a curbstone for the tape recorder and the tv, a desk behind which i do homework, i draw. to tell the truth, on my desk the disorder quite often reigns, and mum is sometimes angry at me for it. over a table - book shelves where there are my textbooks, and also volumes from a series «children's encyclopaedia» which i sometimes like to esteem. on one of shelves i have allocated a place for a corner where has collected various bagatelles for memory of a trip on the sea: beautiful stones, sea cockleshells, souvenirs. i all it has arranged so that every morning, having opened eyes, i could admire beauty which reminds me that soon again there will come summer, and we all family will go again to the tender and warm sea. now you represent, as our apartment looks. come to us on a visit - and you will see, how at us is pure and cosy.