Tense
Whenever possible, construct sentences, paragraphs, etc., using a single tense to retain coherence. Avoid skipping around in time by shifting tense indiscriminately. In general, there are three types of tenses.
Use past tense to present historical information.
A summary report was sent to the member companies in October.
Use future tense to describe distant plans or expectations. Do not use the conditional (would) for future.
The resulting models will be able to predict...
Use present tense to describe anything that has current or timely value for the reader.
The immediate objective of the PRSC program is to monitor, control, and reproduce...
For variations on these basic forms (past perfect, present perfect, future perfect), see tense in the Handbook of Technical Writing.