Gravity means the force that attracts a body toward the center of the earth, or toward any other physical body having mass. For most purposes Newton's laws of gravity apply, with minor modifications to take the general theory of relativity into account.
I am beginning to do the homework.
I began to do the homework.
I will begin the homework later.
A. The huge white van full of holiday packages for everyone came down the street, is the correct way to rewrite the following fragment.
As compared with other sentences, this sentence makes the appropriate use of preposition 'down' followed by the noun, which clarifies the sentence precisely.
In the other sentences B. The huge white van full of holiday packages for everyone rumbling and backfiring. C. The huge white van full of holiday packages for everyone on our whole block. D. The huge white van full of holiday packages for everyone in time for Christmas; does not frame the proper sentences as it joins the sentences abruptly without any direction specification.