"Forget your kit again and you'll be off the team", His coach warned him.

KICK

His coach threatened (a)   if he forgot his kit again.

"If you must go out tonight, at least finish your homework first!" said Sarah's father.

SHOULD

Sarah's father said that if (a)   at least finish her homework first.

"Please don't drive so fast!" Ann begged her boyfriend.

PLEADED

Ann (a)   so fast.

phrasal verb:
to make clear / convince sb of a message

"I just couldn't (a)   my point. They were having none of it!"

planned or performed in cooperation with others:

a (a)   effort

The wizard's powers are starting to (a)   - he's not as powerful as he used to be.

unsure; uncertain; not definite or positive; hesitant

(a)  

Coal, oil, natural gas, and other fuels that are ancient remains of plants and animals.

(a)  

Gases in Earth's atmosphere that trap heat near the surface

(a)  

Number of individuals per unit area

(a)  

A figure indicating how long, on average, a person may be expected to live

(a)  

Why don't we go to Crete for our holiday this year?

She suggested (a)   that year.

Leave the window shut! We don't want to catch our death of cold!

The old man objected (a)   opened.

He (a)   denied having said the remark.