Tony 正在给好朋友 Flora 写明信片，请根据图片内容，选择合适的单词，并用单词的正确形式完成明信片内容。
play read eat do drink sing

5-4-20XX
Hello Flora,
How are you? Today is sunny. We are in a park now. My sisters Amy and Sue ① on the slide. My dad ② bread on the grass. My mum ③ book. I ④ orange juice. Oh, there is a bird in the tree! It ⑤ . We are having a great time here. What are you ⑥ ?
Love,
Tony
Flora Chow
Flat C, 20/F
11 Happy Street
Jing'an District
Shanghai, China

① are playing ② is eating ③ is reading ④ am drinking ⑤ is singing ⑥ doing

本题考查现在进行时的用法，现在进行时的结构为"主语 + be动词(am/is/are) + 动词的现在分词形式"，结合图片场景和给出的备选单词逐一匹配：
1. 图中两个小女孩正在滑梯上玩耍，主语My sisters Amy and Sue是复数，be动词用are，备选词play的现在分词为playing，对应填are playing。
2. 图中爸爸正坐在草地上吃面包，主语My dad是第三人称单数，be动词用is，备选词eat的现在分词为eating，对应填is eating。
3. 图中妈妈正坐在长椅上看书，主语My mum是第三人称单数，be动词用is，备选词read的现在分词为reading，对应填is reading。
4. 图中Tony正在喝橙汁，主语是I，be动词用am，备选词drink的现在分词为drinking，对应填am drinking。
5. 图中树上的小鸟正在唱歌，主语It是第三人称单数，be动词用is，备选词sing的现在分词为singing，对应填is singing。
6. 此处是现在进行时常用问句"What are you doing?"，用来询问对方正在做什么，备选词do的现在分词为doing，对应填doing。