1.The boy learned the poem by heart.

1.男孩背下诗。

2.Irrealizable for my lovingness girl. every little bit，I learn by heart.

2.对最爱人食言，一点一滴，我记在心里。

3.You must keep repeating the lines until they are known by heart.

3.你必须反复朗读几行一直到能背诵为止。

4.This is a proverb and you ought to stick it down and learn it by heart.

4.是谚语, 你得把它抄下来记熟。

5.The rocked rubied wine in the candl-light,love is the same,it needs us to taste slowly by heart.

5.烛光下晃动着深红葡萄酒，爱情一样要用心慢慢品味。

6.The frequency of HF is determined by the ratio of respiratory frequency and heart rate.The results also indicated that nonadditivity of heart rate modulation by sympathetic an...

6.高率是呼吸率与心率之比，低和极低可能与交感和副交感神经调节心率非可加性有关。