The future tense of 'accumulated' is 'will accumulate'.
Accumulated.
The sentence demonstrates the future perfect tense. This tense is used to indicate that an action will be completed before a specific point in the future. In this case, it suggests that by a certain future time, your brother's experience with playing sports will have accumulated to over half of his life.
Were is a past tense form of be. The future tense of be is will be.
past tense is got future tense is will get
Am, is, and are are present tense forms of be. The past tense forms of be are was and were. The future tense of be is will be.
The future tense is will carry.
The future tense of "was" is "will be."
The future tense of "seek" is "will seek." The future tense of "bring" is "will bring."
The future tense is will break.
"Which" is present tense and "will break" is future tense.
Past tense - went. Future tense - will go.
The past tense is rained. The future tense is will rain.