If he had no money, he would sometimes sleep in the situation. (this means actually, he does not have money and he does not sometimes sleep in the situation)
If i can use the phone,i will get a taxi or
If i could use the phone, i will get a taxi
==> both of them are correct (they are used to ask for permission to use the phone)
If I cooked, he will eat it or
If i have cooked, he will eat it
==> I think I'd say If I cooked. . .
If you smoke heavily, the risk will be higher
If you smoke heavily, the risk is higher
=> Both are right. We use the second one if we believe the fact the the risk is higher is always true.
There are 5 types of conditional clause
1- Real in the present/future (If clause: present , Main clause: will+verb)
2- Unreal in the present (if clause: past subjuctive, main clause: conditional simple or conditional continuous (would+verb/would be +present participle))
3- Unreal in the past (if clause : present perfet, main clause: conditional perfect or conditional perfect continuous (would have + past participle or would have + been + present participle))
4- Mixed (if clause : if clause of Type 3, main clause: main clause of Type 2 e. g If I had eaten breakfast this morning, I would not be hungry now)
5- Formula (something always true) (If clause : present simple, main clause: present simple)