What 4-letter word can be written forward, backward or upside down, and can still be read from left to right?

Let's play a word game. Following are some meaningless words that can be completed by adding random letters on either side of the word.

For example, the word "rdo" can be formed into "pardon".

Using the same technique, can you complete the given words?
ecalc
airb
rinci
tibac
uidel
gorit
igna
eyho

Which English verb becomes past tense just by rearranging the letters?

What goes up but never comes down?

I am the black child of a white father, a wingless bird, flying even to the clouds of heaven. I give birth to tears of mourning in pupils that meet me, even though there is no cause for grief, and at once on my birth, I am dissolved into air. What am I?

The more it dries, the wetter it becomes. Can you tell what it is?

It is always ahead of me yet I can never see it. What is it?

What is always in front of you but can’t be seen?

What is in seasons, seconds, centuries and minutes but not in decades, years or days?

I speak without a mouth, and hear without ears. I have no-body, but I come alive with the wind. What am I?