As stated before miners do not get a block to mine, they compose it from data like pending transactions, previous block info and an (unknown) number they need to guess.
As some info of the previous block is included in the next block a block can only be mined if the previous block is mined. Finding the next block involves not only hash power but also some luck. Not all miners find (and publish) a next block the same time.
In theory you can mine a several of blocks and wait to publish them after you mined e.g. 100 blocks. However in that case is is not sufficient to mine one block faster than all the other miners; you need to mine all this 100 blocks faster than all other miners together. This would be a race very difficult to win (also due to the luck involved), and if you lose or are not significant ahead of all other miners after this 100 blocks you will not receive any reward.