Combine sentence and use coordinate conjection:

1) my bus driver is strict .
she is friendly.
( compund sentence )

2) the engine sputtered.
then it died
( compund verb )

Coordinating conjunctions include for, and, nor, but, or, yet, and so.  
 
To connect the following sentences using coordinating conjunctions, you can say:
1.    She is friendly, but my bus driver is strict. (The coordinating conjunction used here is “but”.) However, for this sentence to make sense, there has to be a preceding sentence that can further expound the antecedent of the pronoun “she”.

2.    The engine sputtered, and then it died. (The coordinating conjunction used here is “and”.)

I’m going to guess #4 since that seems pretty logical.