Look! A group of students _____ under the big tree.
[ ]
A. is reading.
B. to read
C. reading
D. reads
B. to read
C. reading
D. reads
—What are you doing?
—I ____ a letter to my pen pal.
—I ____ a letter to my pen pal.
[ ]
A. write
B. am writing
C. writes
D. am write
B. am writing
C. writes
D. am write