坐着的时候后背要挺直。
Keep back straight and bend knees.
背要直，只弯两膝。
You should keep your back straight.
你应该把后背挺直。
She held her head erect and her back straight.
她昂着头，把背挺得笔直。
Our teacher always keeps his back straight.
我们的老师总是把背挺得笔直。
Bent your knees, but keep your back straight.
屈膝，保持背部挺直。
Sit with back straight, hands at side on floor.
坐姿后背伸直，手放于身体两侧的地面上。
Keep your back straight. Thighs tight and shoes right.
保持你的腰背挺直，大腿绷紧和鞋子穿对。
Sit with knees bent, feet flat on floor, back straight.
屈膝坐立，保持后背伸直，脚平贴地面。
Your head should be up, your back straight, and shoulders level.
你的头应该抬起来，你的背部笔直，肩膀水平。
Sit or lie down comfortably with your back straight and close your eyes.
找一个舒适的地方躺下或坐下，背部平直，闭上你的眼睛。
Sit in a comfortable position with your back straight, and close your eyes.
在一个舒服的地方坐下，挺直腰板，然后闭上你的眼睛。
Sit with back straight, legs in front, slightly spread with knees straight.
坐姿背伸直，腿于身前，膝关节伸直稍稍分开。
Let the baby lie face down on the bed, keeping the back straight and relax.
让宝宝俯卧于床上，背部保持平直，放松。
Some debtholders did not get their money back straight away, a technical default.
一些债务持有人没有直接拿到他们的钱，这是技术上的违约。
He explained that walking backward forces the tummy in and the back straight.
他解释说，倒退行走能帮助人收缩腹部，并且能保持背部挺直。
When you lift, squat close to the object with your back straight and head up.
当你要搬运重物时，你应该在它附近蹲下来，并挺直你的背，抬起你的头。
Keeping your back straight, push up with your arms until your arms are extended.
保持背部挺直，向上推你的手臂直到手臂伸直。
Squat down as low as you can, keeping your heels on the ground and your back straight.
深蹲至最低位置，脚跟贴紧地面，背部挺直。
Walk with a purposeful stride, with your back straight and with your head held up high!
大步走，挺直腰，抬起头。
Standing straight with your feet shoulder-width apart, slowly lower your body, back straight.
双脚分开站立，与肩同宽，缓慢下蹲，背部挺直。
Find a comfortable chair or bench and sit with your back straight and your feet flat on the floor.
找一个舒适的椅子或板凳，直背而坐，双脚平放于地面。
Keep your posture straight and erect. Your head should be up, your back straight, and shoulders level.
保持您的姿势挺而直，抬起头，挺直腰，双肩水平。
Bend forward slightly at the hip, keeping your back straight, until you feel a slight stretch in your hamstrings.
保持背部平直慢慢俯身，直到感觉腿筋拉紧。
Have your front leg straight your arms comfortably extended but not locked out your back straight and your head up.
前腿伸直，手臂自然伸展，但是不要停止运动，抬头挺胸。
Set your feet shoulder-width apart, and keep your knees slightly bent, back straight, and eyes focused straight ahead.
双脚与肩同宽，保持膝部稍弯，后背挺直，双眼注视前方。
I had to sit on my stool with back straight and upright, correctly holding the brush, so I loved making random drawings.
而我却得挺着腰、直着背、握着笔、坐在小板凳上，所以我还是喜欢乱画。
Keep your back straight, head up and turned towards the target, and straighten your bow arm, but keep the elbow unlocked.
保持背部的挺直，头转向目标，伸直你的持弓臂，同事保持肘部的放松。
We taught the second boy, who was writing his homework on a dwarf table when we entered, to stand with his back straight, head held up.
我进入第二个男孩子的家时，他正趴在家里的矮桌上写作业，我教他挺直了背，抬起头，标准了写作业的姿势，为了他的身体健康。
We taught the second boy, who was writing his homework on a dwarf table when we entered, to stand with his back straight, head held up.
我进入第二个男孩子的家时，他正趴在家里的矮桌上写作业，我教他挺直了背，抬起头，标准了写作业的姿势，为了他的身体健康。
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