19．
Naturally，American schoolchildren love holidays．And they get a lot of them each year．
Besides having national holidays such as Thanksgiving and Presidents'Day off from school，students get longer breaks in the spring and during the summer holidays．In fact，kids in US only go to school for about 180days a year．To students，holidays are perfect．However，parents think there are advantages and disadvantages．
On the one hand，school holidays allow families to spend time together．Many American parents take time off from work during June，July or August to travel with their children on vacation either in US or a foreign country．On the other hand，schoolchildren get much more time off school than parents get vacation time．This means that parents with young children may have to pay more in babysitting or daycare costs．As well，the long summer holidays mean that students sometimes get bored．
Besides going on trips with their parents，American students enjoy taking part in different kinds of activities during the holidays．For example，some kids enjoy summer camps and outdoor adventure（冒險） holidays．Such trips are great for adventurous students． They also have a lot to offer students who aren't usually interested in traditional PE activities．You can do courses in survival（生存） skills，for example．Students learn how to make a camp in the forest，which wild food they can eat and how to find their way back to the center．
Students who are not excited about summer camps and outdoor adventure may take part in courses in computer game design，filmmaking and photography during the holidays．Finally，the traditional school trip to foreign countries is always popular．Students can practice their foreign language skills and experience everyday life in a different culture．
77．How long are kids in the US at school every year？A
A．About 180 days． B．About 280 days．
C．About 200 days． D．About 300 days．
78．What does the underlined word"They"refer to in the third paragraph？D
A．Some kids． B．Different traditional PE activities
C．Parents D．Summer camps and outdoor adventure．
79．Which of the following is true？C
A．Both parents and students think school holidays are perfect．
B．Parents can take care of their young children during all the holidays．
C．Students enjoy taking part in different kinds of activities during holidays．
D．Students don't like to have school trips to foreign countries during holidays．
80．What would be the best title for the passage？B
A．School Trips in the US． B．School Holidays in the US．
C．School activities in the US． D．Outdoor Adventure in the US．
Have you ever thought about one question：why do we need to learn math？
-Which class are you in？