___have you been to America?Only once.A.How often B.How much

___have you been to America?Only once.A.How often B.How much time C.How many times D.How long
____of the students will take part in the sports meet.A.Three four B.Three-fourths C,Three-four D.Three-fourth I haven't been to London and I haven't been to America,____.A.too B.either C.also D.neither ______ it rained heavily this morning,___all of us reached the school on time.A.Although...but B./...though C.Though...but D./...but 保证全对+讲清理由加20分
题有点紧凑，看清楚。

1 C 问次数.（ 根据ONLY ONCE 只有一次,可知）
分析：A 问频繁； B 问时间； D 问长度‘ 多长’
2 B
分数的表达法：分子用基数词,分母用序数词,分子大于1,分母加S
3 B 也,用于 否定句中
分析：A 肯定句尾； C 肯定句中；D 两者都不.
4 D 虽然……但是……
分析：although / though不能与 but 连用.
加油!不明白再问!