I'll do a couple, and maybe other members will do the rest.
1. Without companions, he stood alone _________ the street.
(A) at (B) in (C) on (D) with
"In the street" would be correct in British English. But it's possible that "on the street" would be ok in American English.
2.She was in a bad mood, so she kept _______ for almost two hours.
(A) laughing (B) happy (C) crying (D) nagging
"In a bad mood" usually means "quite angry about something". "Nagging" is therefore the better choice, to my mind. (But sometimes people cry when they're angry!)
3. To solve problems wisely, we need a lot of patience and _______.
(A) intelligence (B) smart (C) good luck (D) intelligent
We need good luck to solve problems sometimes; but if we need good luck, we can't be said to have solved the problems "wisely".
4. After World War Two the Soviet Union took back most of the territory in Eastern Europe that had once been part of the Russian empire. It also set up Communist governments in the military ties __________.
The second sentence makes no sense to me, with or without the missing words.
5. and 6
This text is quite poorly written:
For some nations in Africa [add comma]
water is a very important source [source of what?]
because it can be used to irrigate [what do you use to irrigate something, if not water?]
farmland. Many wars had occurred in the history for fighting for the ownership of water source. ] This sentence is bizarre in the extreme. It is at best ungrammatical.
In recent times, those countries have learned how to build dams ____(5)____ the rivers] "along" is ok.
to control the flow of the water. Some people regard these dams as necessary for irrigation; others worry that the dams may cause harm to plant and animal life, and even to farmland. In addition, governments have had disagreements ____(6)____ ] "about" is correct here. "On" would belong to a different register.
I hope that helps you with your decision!
All the best,