i still confuse if why the primer had to removed after the dna replication?

Question

if the primer is removed, isn't it mean that the bases bind with the primer would became alone after the primer is removed.

Answer 1

The primer has to be removed because it's formed by RNA, and not DNA.
After the rest of the strand has been completed, the DNA-polymerase I is able to act as an exonuclease (=nucleotid remover) and eliminate the RNA nucleotides that formed the primer; then, again acting as polymerase, it replaces them by DNA nucleotides (remember that it can "read" the complementary chain, so it inserts the appropriate bases). Thus, each of the nucleotides that were formerly attached to the primer receive their complementary base, and the new DNA double strand is complete.
Another enzyme, the DNA-ligase, eliminates the little gaps left between adjacent new fragments by catalizing the formation of new phosphodiester unions between the nucleotids.

Answer 2

I am pretty sure it is the DNA polymerase that is removed not the primer.