对此，有些家长表示，真的很难做到啊......Photo by Hal Gatewood on Unsplash
Babies and toddlers should not be left to passively watch TV or other screens, according to new World Health Organization guidelines.
Sedentary screen time, including computer games, should not happen before a child is two, the WHO says.
sedentary ['sed(ə)ntəri]: adj.需要久坐的；惯于久坐不动的
The limit for two- to four-year-olds is an hour a day and less is better.
The new WHO advice focuses on passive viewing - youngsters being placed in front of a TV or computer screen or handed a tablet or mobile phone for entertainment - and is aimed at tackling child inactivity, a leading risk factor for global mortality and obesity-related ill health.
It is the first time the WHO has made recommendations on physical activity, sedentary behavior and sleep for children under five.
As well as warning against passive screen time, it says babies should not spend longer than an hour at a time strapped into a buggy, car seat or sling.
buggy['bʌɡi]: n. 童车
Be physically active several times a day, including at least 30 minutes' "tummy time" - lying on their front每天做数次运动，包括至少30分钟的俯卧
No sedentary screen time不能久坐看屏幕
14-17 hours' sleep a day, including naps, for newborns - reducing to 12-16 by four to 11 months新生儿每天睡14到17个小时（包括打盹），4-11月婴儿每天睡12到 16个小时
Should not be restrained (ie strapped into a recliner, seat or sling) for more than an hour at a time坐在躺椅、座椅或背带上一次不能超过一个小时
For one- and two-year-olds:一岁到两岁幼儿：
At least three hours' physical activity a day每天至少活动三个小时
No sedentary screen time for one-year-olds and less than an hour for two-year-olds一岁幼儿不能久坐看屏幕，两岁幼儿看屏幕时间要少于1个小时
11-14 hours' sleep a day, including naps每天睡11到14个小时，包括打盹
Should not be restrained for more than an hour at a time or sit for extended periods of time坐在童车、背带或座椅上的时间一次不能超过一个小时
For three- and four-year-olds:三岁到四岁儿童：
At least three hours' physical activity a day, including at least one of moderate or vigorous intensity每天至少活动三个小时，包括至少一次中高强度的锻炼
Up to an hour of sedentary screen time - less is better久坐看屏幕的时间最好不要超过一个小时
10-13 hours' sleep a day, which may include a nap每天睡10到13个小时，包括午休
Should not be restrained for more than an hour at a time or sit for extended periods of time坐在童车或座椅上的时间一次不能超过一个小时
The WHO advice is based on available evidence, but there is still a lack of definitive research into the harms and possible benefits of screen use.
However, it was unlikely very young children gained from passive, sedentary viewing, said one of the guideline authors, Dr Juana Willumsen.
"Children need to be given opportunities throughout the day to actively play and we should be reducing sedentary, passive screen time," she said.
In the US, experts say children should not use screens before they are 18 months old.
In Canada, screen time for children younger than two is not recommended.
Dr Max Davie, from the RCPCH, said: "The restricted screen time limits suggested by the WHO do not seem proportionate to the potential harm.
"Our research has shown that currently there is not strong enough evidence to support the setting of screen time limits. "
Paula Morton, a teacher and mother of two young children, said her son learned a lot from watching programs about dinosaurs and came out with "random facts about them".
random fact: 冷知识
"He doesn't just sit there and zone out," she said. "He's obviously thinking and using his brain.
zone out: 头脑空白，走神
"I don't know how I would make the dinner, cook and clean if he didn't have something to watch."
Is screen time controlled?屏幕时间是否得到控制？
Does screen use interfere with what your family want to do?屏幕使用是否干扰了家庭计划？
Does screen use interfere with sleep?屏幕使用是否干扰了睡眠？
Are you able to control snacking during screen time?你能控制孩子在屏幕时间不吃零食吗？
If a family are satisfied with their answers to these questions, then they are likely to be handling screen time well, the college says.