A.5歲?6歲B.7歲?8歲C.20歲?30歲D.10歲?15歲
A.1歲?1.5歲B.4歲?5歲C.2.5歲?3歲D.8個(gè)月?10個(gè)月
A.6個(gè)月?8個(gè)月B.5個(gè)月?6個(gè)月C.12個(gè)月?15個(gè)月D.36個(gè)月?42個(gè)月